Emerald ash borer (EAB), Agrilus planipennis, is a phloem-boring beetle, native to East Asia that... more Emerald ash borer (EAB), Agrilus planipennis, is a phloem-boring beetle, native to East Asia that has become a serious invasive pest of ash (Fraxinus spp.) trees in North America and European Russia since the early 2000s. In 2019, EAB was detected in Ukraine. It had spread over 300 km from the entry point over two years and killed hundreds of Fraxinus excelsior and F. pennsylvanica trees. EAB poses a threat to the ash forests of neighboring European countries, which have already been damaged by the invasive fungus Hymenoscyphus fraxineus. The purpose of this research was (i) to reveal the traits of EAB and the climatic variables that affect its survival; (ii) to predict the EAB expansion range in Ukraine and westward; and (iii) to compare the most significant bioclimatic variables in the native, invasive ranges of EAB, as well as outside these ranges. The results demonstrated the following: (i) in all ranges, EAB has adapted to the seasonal temperature variations; (ii) the MaxEnt mo...
During the past 150 years, only a few incidents have been recorded of more than 50,000 m3 being d... more During the past 150 years, only a few incidents have been recorded of more than 50,000 m3 being damaged by wind activity in the Moravian-Silesian Beskids. Such events occur with a frequency of approximately 25 years. Wind damage correlates with prevailing winds. Scattered forest damage is more prevalent than extensive areas of wind-fallen trees. The relative area of comprehensively damaged forests significantly correlates with increasing elevation above sea level. Historical references to snow-caused tree falls during which the volume of damaged wood exceeded 20,000 m3 are documented for several years. These occur with a frequency of approximately 10 years. No significant logistic regression has been determined between the maximum elevation of snow cover at the Lysá hora station and the probability for the incidence of damages to exceed 20,000 m3. No significant relationship has been determined between the duration of drought and unregulated fellings in the following year. For the p...
Detailed characteristics (tree species composition, tree representation, identification features)... more Detailed characteristics (tree species composition, tree representation, identification features) are presented by 3rd (i.e. geobiocenoses of Querci-fageta s. lat.) and 4th (Fageta (abietis) s. lat.) vegetation tiers in north-eastern Moravia and Silesia. 3rd VT occupies 45.6% of the study area – from 190 m a.s.l. up to 430 m a.s.l. Fagus sylvatica is a dominant tree (with the height of 35–40 m). Quercus robur and Quercus petraea have their ecological optimums there with the representation of up to 30%. Abies alba occurs in the crown level with the representation of up to 10%. 4th occupies 35.2% of the study area – from 310 m a.s.l. up to 650 m a.s.l. Fagus sylvatica is dominant (the height over 50 m). Abies alba occurs in the co-dominant level (sporadically in the level exceeding the main level) with the representation of ±20% and the height of up to 50 m. Quercus petraea and Quercus robur occur only as an interspersed species with the representation of up to 10%, they do not reach ...
Kočárek, Petr, Holuša, Jaroslav (2007): Nomen nudum Isophya tatrica Mařan, 1957, belongs to I. ca... more Kočárek, Petr, Holuša, Jaroslav (2007): Nomen nudum Isophya tatrica Mařan, 1957, belongs to I. camptoxypha Fieber, 1853 (Orthoptera: Tettigoniidae). Acta Entomologica Musei Nationalis Pragae 47: 1-2
The main goal of work was to compare the flight activity of Trypodendron lineatum, T. domesticum ... more The main goal of work was to compare the flight activity of Trypodendron lineatum, T. domesticum and T. laeve in Central Europe. Field trapping experiments were conducted in 70- to 100-year-old Norway spruce stands located at three study sites in the Czech Republic. At each study site five pheromone traps were used. Pheromone-baited, black, window-slot traps (Theysohn, Germany) were used. Traps were placed at log landing areas 10-15 m apart from the nearest forest edge. Each trap was baited with a standard synthetic pheromone lure, XL Ecolure (Fytofarm, Slovakia). Three species of Trypodendron were recorded. T. lineatum was the most abundant, followed by T. domesticum and T. laeve . Flight activity began at the end of March or in mid-April. Only one another peak of the flight activity of T. lineatum and T. domesticum was observed at one study site in May 2011. Statistically significant relationships were found between catches of all species with the exception of T. lineatum vs. T. l...
Some bark beetles of genus Ips occuring in Europe attack multiple tree hosts. is probably expla... more Some bark beetles of genus Ips occuring in Europe attack multiple tree hosts. is probably explains why some of the bark beetle diseases have also more hosts. For example Gregarina typographi was known from all of six analysed species and Chytridiopsis typographi from midgut epithelium of ve species of the genus Ips. On the other hand there is only one known species-speci c pathogen Larssoniella typographi described in Ips duplicatus. At present, around twenty species of pathogens were described in bark beetle subfamily Scolytinae, out of which ten are known in the spruce bark beetle Ips typographus. For most pathogens, only rare information is available about in uence on beetles: on the vitality, fertility, ight ability, hibernation, etc. Moreover, most experiments are conducted under laboratory conditions. In this paper we summarize the knowledge of pathogens (viruses, protozoa, fungi) and parasitic nematodes and give a comprehensive overview of detected pathogens in di erent ...
Notopygus bicarinatus teunissen, 1953 is parasitoid of web-spinning sawflies of the genus Cephalc... more Notopygus bicarinatus teunissen, 1953 is parasitoid of web-spinning sawflies of the genus Cephalcia. this species was found near větrný Jenikov. the first record from Bohemia including Cephalcia lariciphila as a new additional host. N. bicarinatus oviposit into the larvae of C. lariciphila when borrowing in soil in the late May. the infestation of Cephalcia prepupae is not high and varied within the range of 3.5–6.1% during test period 2003–2005.
In stands with the majority of spruce and aged over 70 years, 35 sample plots were laid out (in t... more In stands with the majority of spruce and aged over 70 years, 35 sample plots were laid out (in total 700 trees) in the vicinity of Anenský vrch Hill at altitudes over 800 m above sea level. In the course of the growing season 2005, the following parameters were determined: total defoliation, defoliation of the primary structure, percentage of secondary shoots, presence and extent of yellowing and browning. In 10 selected trees, branches were taken from crowns for morphological analyses and annual length increments of branches and numbers of secondary shoots in the particular years were determined. Total defoliation and the occurrence of yellowing were related to slope orientation and position of the plot towards the ridge. The number of shoots produced in the given year correlated with the level of annual NO 3 deposition. The determined difference in the occurrence of yellowing between limed and unlimed plots cannot be interpreted unambiguously because limed and unlimed plots differ in exposure at the same time. The determined importance of slope orientation for the health condition of a stand shows that under the simultaneous air pollution load climatic factors are a factor deciding on the resulting effect of the synergetic action of stressors on forest stands.
This is a self-archived version of an original article. This version may differ from the original... more This is a self-archived version of an original article. This version may differ from the original in pagination and typographic details.
The European spruce bark beetle Ips typographus L. causes significant economic losses in managed ... more The European spruce bark beetle Ips typographus L. causes significant economic losses in managed coniferous forests in Central and Northern Europe. New infestations either occur in previously undisturbed forest stands (i.e., spot initiation) or depend on proximity to previous years’ infestations (i.e., spot spreading). Early identification of newly infested trees over the forested landscape limits the effective control measures. Accurate forecasting of the spread of bark beetle infestation is crucial to plan efficient sanitation felling of infested trees and prevent further propagation of beetle-induced tree mortality. We created a predictive model of subsequent year spot initiation and spot spreading within the TANABBO decision support system. The algorithm combines open-access Landsat-based vegetation change time-series data, a digital terrain model, and forest stand characteristics. We validated predicted susceptibility to bark beetle attack (separately for spot initiation and sp...
Five types of stand stages (clearings-samplings, plantations, thinnings, thickets, and mature for... more Five types of stand stages (clearings-samplings, plantations, thinnings, thickets, and mature forests) of spruce forests were examined at the foothills of the Jizerské hory Mts. in summer 2005 and 2006. The presence of ants was surveyed by catching them into pitfall traps and observing on baits. Higher numbers of Formica fusca ants were found in clearings-samplings and in plantations. Their activity was higher at the soil and air temperature of 20–30°C. The peak of activity was observed in July. Most specimens were trapped at lighter habitats and in the sites with more than 50% herbaceous and gramineous vegetation cover. F. pratensis was trapped in plantations and thickets. It was active at the soil temperatures 12–21°C and air temperatures 16–25°C. It occurred both in dark and light areas. F. sanguinea most commonly occurred in thinnings. This species was the most active at the soil temperature 20–30°C. Its activity depending on air temperature grew almost linearly. It occurred bot...
Neuropteroid insects (Neuroptera, Raphidioptera) and scorpion flies (Mecoptera) were studied in s... more Neuropteroid insects (Neuroptera, Raphidioptera) and scorpion flies (Mecoptera) were studied in six young spruce forest localities in the eastern part of the Czech Republic during years 2005 and 2006. Twenty-seven species of lacewings, four species of snake flies and four species of scorpion flies were found using the Malaise traps. Consequently, the seasonal flight activity of the seven most abundant species (Chrysopa perla, Hemerobius pini, Hemerobius humulinus, Dichrostigma flavipes, Phaeostigma notata, Panorpa communis and Panorpa germanica) is discussed.
Spruce is regarded as the only host plant of Ips duplicatus in Central Europe, whereas this beetl... more Spruce is regarded as the only host plant of Ips duplicatus in Central Europe, whereas this beetle exceptionally occurs on pine in Siberia. Its occurrence on Pinus strobes and Pinus sylvestris was discovered in the eastern part of the Czech Republic and in southern Poland, where the population density of Ips duplicatus has been increased for a long time on Norway spruce. However, all cases concerned only single trees which were growing in forest complexes with spruce dominance. The most likely explanation is merely a consequence of the typical host plant shortage.
Several methods of Pristiphora abietina adults catching were compared (Malaise trap, white and ye... more Several methods of Pristiphora abietina adults catching were compared (Malaise trap, white and yellow sticky boards, sweeping). The yellow sticky boards are handy in the field, and under the high population density appear to be a reliable method of detecting sawfly populations: 1. There was a statistically significant coincidence between the samples of Malaise traps and yellow sticky boards. 2. There was a highly significant linear correlation between the number of caught adults on five sticky boards and the degree of defoliation in seven localities. 3. We did not observe any statistically significant differences between the samples on yellow sticky boards taken in different intervals. To estimate the abundance of adults, it is sufficient to install yellow sticky boards before swarming and check them after the swarming. 4. No statistically significant differences were found between the catch means per board in line with different number of boards, it means with different distance, i...
In total, 55,862 specimens of seven species of the genus Cephalcia (C. abietis, C. arvensis, C. a... more In total, 55,862 specimens of seven species of the genus Cephalcia (C. abietis, C. arvensis, C. alashanica, C. alpina, C. annulicornis, C. erythrogaster, C. masuttii) were collected using Malaise traps in spruce mountain forests from 2001 to 2006. Sex ratio was male biased as a result of used methods; males are more active and quicker. The flight activity started in the studied localities at the beginning of May or the beginning of June depending on the actual weather. C. alpina flew first, followed by C. erythrogaster and C. arvensis, the last flying species were C. alashanica and C. abietis. C. abietis was the most abundant in all localities within all years (total dominance of 93%). C. arvensis, C. alashanic and C. alpina were collected in more than hundred of specimens while C. annulicornis, C. erythrogaster and C. masuttii were collected only occasionally. Environmental variables were tested with the RDA model which proved several of them (years of 2001–2003, 2006, Český les an...
In the Czech Republic, A. nebulosus occurs in coniferous, deciduous as well as in mixed forests, ... more In the Czech Republic, A. nebulosus occurs in coniferous, deciduous as well as in mixed forests, in lowland forests and even on forest-steppe habitats. Larvae occur mainly on Picea sp., Pinus sp. and Abies sp.; adults occur on the same tree species and also on Larix sp., Quercus sp., Salix sp. and Fagus sp. Adults overwinter in the bark of several coniferous trees with thicker bark (mainly Pinus sylvestris L. and Larix decidua Mill.) where they are hidden in cracks. Woodpeckers attack such trees with masses ofA. nebulosus very intensively. In five localities with Malaise traps in the Nízký Jeseník Hills, the flight activity started at the beginning of May and ended in mid-June with the peak at the end of May and beginning of June in 2005. In 2006, the flight activity started later in mid-May and lasted to the beginning of July but was interrupted by cold and rainy weather. At higher altitudes were beetles sampled only in the first half of June in 2006. The size of males and females ...
Emerald ash borer (EAB), Agrilus planipennis, is a phloem-boring beetle, native to East Asia that... more Emerald ash borer (EAB), Agrilus planipennis, is a phloem-boring beetle, native to East Asia that has become a serious invasive pest of ash (Fraxinus spp.) trees in North America and European Russia since the early 2000s. In 2019, EAB was detected in Ukraine. It had spread over 300 km from the entry point over two years and killed hundreds of Fraxinus excelsior and F. pennsylvanica trees. EAB poses a threat to the ash forests of neighboring European countries, which have already been damaged by the invasive fungus Hymenoscyphus fraxineus. The purpose of this research was (i) to reveal the traits of EAB and the climatic variables that affect its survival; (ii) to predict the EAB expansion range in Ukraine and westward; and (iii) to compare the most significant bioclimatic variables in the native, invasive ranges of EAB, as well as outside these ranges. The results demonstrated the following: (i) in all ranges, EAB has adapted to the seasonal temperature variations; (ii) the MaxEnt mo...
During the past 150 years, only a few incidents have been recorded of more than 50,000 m3 being d... more During the past 150 years, only a few incidents have been recorded of more than 50,000 m3 being damaged by wind activity in the Moravian-Silesian Beskids. Such events occur with a frequency of approximately 25 years. Wind damage correlates with prevailing winds. Scattered forest damage is more prevalent than extensive areas of wind-fallen trees. The relative area of comprehensively damaged forests significantly correlates with increasing elevation above sea level. Historical references to snow-caused tree falls during which the volume of damaged wood exceeded 20,000 m3 are documented for several years. These occur with a frequency of approximately 10 years. No significant logistic regression has been determined between the maximum elevation of snow cover at the Lysá hora station and the probability for the incidence of damages to exceed 20,000 m3. No significant relationship has been determined between the duration of drought and unregulated fellings in the following year. For the p...
Detailed characteristics (tree species composition, tree representation, identification features)... more Detailed characteristics (tree species composition, tree representation, identification features) are presented by 3rd (i.e. geobiocenoses of Querci-fageta s. lat.) and 4th (Fageta (abietis) s. lat.) vegetation tiers in north-eastern Moravia and Silesia. 3rd VT occupies 45.6% of the study area – from 190 m a.s.l. up to 430 m a.s.l. Fagus sylvatica is a dominant tree (with the height of 35–40 m). Quercus robur and Quercus petraea have their ecological optimums there with the representation of up to 30%. Abies alba occurs in the crown level with the representation of up to 10%. 4th occupies 35.2% of the study area – from 310 m a.s.l. up to 650 m a.s.l. Fagus sylvatica is dominant (the height over 50 m). Abies alba occurs in the co-dominant level (sporadically in the level exceeding the main level) with the representation of ±20% and the height of up to 50 m. Quercus petraea and Quercus robur occur only as an interspersed species with the representation of up to 10%, they do not reach ...
Kočárek, Petr, Holuša, Jaroslav (2007): Nomen nudum Isophya tatrica Mařan, 1957, belongs to I. ca... more Kočárek, Petr, Holuša, Jaroslav (2007): Nomen nudum Isophya tatrica Mařan, 1957, belongs to I. camptoxypha Fieber, 1853 (Orthoptera: Tettigoniidae). Acta Entomologica Musei Nationalis Pragae 47: 1-2
The main goal of work was to compare the flight activity of Trypodendron lineatum, T. domesticum ... more The main goal of work was to compare the flight activity of Trypodendron lineatum, T. domesticum and T. laeve in Central Europe. Field trapping experiments were conducted in 70- to 100-year-old Norway spruce stands located at three study sites in the Czech Republic. At each study site five pheromone traps were used. Pheromone-baited, black, window-slot traps (Theysohn, Germany) were used. Traps were placed at log landing areas 10-15 m apart from the nearest forest edge. Each trap was baited with a standard synthetic pheromone lure, XL Ecolure (Fytofarm, Slovakia). Three species of Trypodendron were recorded. T. lineatum was the most abundant, followed by T. domesticum and T. laeve . Flight activity began at the end of March or in mid-April. Only one another peak of the flight activity of T. lineatum and T. domesticum was observed at one study site in May 2011. Statistically significant relationships were found between catches of all species with the exception of T. lineatum vs. T. l...
Some bark beetles of genus Ips occuring in Europe attack multiple tree hosts. is probably expla... more Some bark beetles of genus Ips occuring in Europe attack multiple tree hosts. is probably explains why some of the bark beetle diseases have also more hosts. For example Gregarina typographi was known from all of six analysed species and Chytridiopsis typographi from midgut epithelium of ve species of the genus Ips. On the other hand there is only one known species-speci c pathogen Larssoniella typographi described in Ips duplicatus. At present, around twenty species of pathogens were described in bark beetle subfamily Scolytinae, out of which ten are known in the spruce bark beetle Ips typographus. For most pathogens, only rare information is available about in uence on beetles: on the vitality, fertility, ight ability, hibernation, etc. Moreover, most experiments are conducted under laboratory conditions. In this paper we summarize the knowledge of pathogens (viruses, protozoa, fungi) and parasitic nematodes and give a comprehensive overview of detected pathogens in di erent ...
Notopygus bicarinatus teunissen, 1953 is parasitoid of web-spinning sawflies of the genus Cephalc... more Notopygus bicarinatus teunissen, 1953 is parasitoid of web-spinning sawflies of the genus Cephalcia. this species was found near větrný Jenikov. the first record from Bohemia including Cephalcia lariciphila as a new additional host. N. bicarinatus oviposit into the larvae of C. lariciphila when borrowing in soil in the late May. the infestation of Cephalcia prepupae is not high and varied within the range of 3.5–6.1% during test period 2003–2005.
In stands with the majority of spruce and aged over 70 years, 35 sample plots were laid out (in t... more In stands with the majority of spruce and aged over 70 years, 35 sample plots were laid out (in total 700 trees) in the vicinity of Anenský vrch Hill at altitudes over 800 m above sea level. In the course of the growing season 2005, the following parameters were determined: total defoliation, defoliation of the primary structure, percentage of secondary shoots, presence and extent of yellowing and browning. In 10 selected trees, branches were taken from crowns for morphological analyses and annual length increments of branches and numbers of secondary shoots in the particular years were determined. Total defoliation and the occurrence of yellowing were related to slope orientation and position of the plot towards the ridge. The number of shoots produced in the given year correlated with the level of annual NO 3 deposition. The determined difference in the occurrence of yellowing between limed and unlimed plots cannot be interpreted unambiguously because limed and unlimed plots differ in exposure at the same time. The determined importance of slope orientation for the health condition of a stand shows that under the simultaneous air pollution load climatic factors are a factor deciding on the resulting effect of the synergetic action of stressors on forest stands.
This is a self-archived version of an original article. This version may differ from the original... more This is a self-archived version of an original article. This version may differ from the original in pagination and typographic details.
The European spruce bark beetle Ips typographus L. causes significant economic losses in managed ... more The European spruce bark beetle Ips typographus L. causes significant economic losses in managed coniferous forests in Central and Northern Europe. New infestations either occur in previously undisturbed forest stands (i.e., spot initiation) or depend on proximity to previous years’ infestations (i.e., spot spreading). Early identification of newly infested trees over the forested landscape limits the effective control measures. Accurate forecasting of the spread of bark beetle infestation is crucial to plan efficient sanitation felling of infested trees and prevent further propagation of beetle-induced tree mortality. We created a predictive model of subsequent year spot initiation and spot spreading within the TANABBO decision support system. The algorithm combines open-access Landsat-based vegetation change time-series data, a digital terrain model, and forest stand characteristics. We validated predicted susceptibility to bark beetle attack (separately for spot initiation and sp...
Five types of stand stages (clearings-samplings, plantations, thinnings, thickets, and mature for... more Five types of stand stages (clearings-samplings, plantations, thinnings, thickets, and mature forests) of spruce forests were examined at the foothills of the Jizerské hory Mts. in summer 2005 and 2006. The presence of ants was surveyed by catching them into pitfall traps and observing on baits. Higher numbers of Formica fusca ants were found in clearings-samplings and in plantations. Their activity was higher at the soil and air temperature of 20–30°C. The peak of activity was observed in July. Most specimens were trapped at lighter habitats and in the sites with more than 50% herbaceous and gramineous vegetation cover. F. pratensis was trapped in plantations and thickets. It was active at the soil temperatures 12–21°C and air temperatures 16–25°C. It occurred both in dark and light areas. F. sanguinea most commonly occurred in thinnings. This species was the most active at the soil temperature 20–30°C. Its activity depending on air temperature grew almost linearly. It occurred bot...
Neuropteroid insects (Neuroptera, Raphidioptera) and scorpion flies (Mecoptera) were studied in s... more Neuropteroid insects (Neuroptera, Raphidioptera) and scorpion flies (Mecoptera) were studied in six young spruce forest localities in the eastern part of the Czech Republic during years 2005 and 2006. Twenty-seven species of lacewings, four species of snake flies and four species of scorpion flies were found using the Malaise traps. Consequently, the seasonal flight activity of the seven most abundant species (Chrysopa perla, Hemerobius pini, Hemerobius humulinus, Dichrostigma flavipes, Phaeostigma notata, Panorpa communis and Panorpa germanica) is discussed.
Spruce is regarded as the only host plant of Ips duplicatus in Central Europe, whereas this beetl... more Spruce is regarded as the only host plant of Ips duplicatus in Central Europe, whereas this beetle exceptionally occurs on pine in Siberia. Its occurrence on Pinus strobes and Pinus sylvestris was discovered in the eastern part of the Czech Republic and in southern Poland, where the population density of Ips duplicatus has been increased for a long time on Norway spruce. However, all cases concerned only single trees which were growing in forest complexes with spruce dominance. The most likely explanation is merely a consequence of the typical host plant shortage.
Several methods of Pristiphora abietina adults catching were compared (Malaise trap, white and ye... more Several methods of Pristiphora abietina adults catching were compared (Malaise trap, white and yellow sticky boards, sweeping). The yellow sticky boards are handy in the field, and under the high population density appear to be a reliable method of detecting sawfly populations: 1. There was a statistically significant coincidence between the samples of Malaise traps and yellow sticky boards. 2. There was a highly significant linear correlation between the number of caught adults on five sticky boards and the degree of defoliation in seven localities. 3. We did not observe any statistically significant differences between the samples on yellow sticky boards taken in different intervals. To estimate the abundance of adults, it is sufficient to install yellow sticky boards before swarming and check them after the swarming. 4. No statistically significant differences were found between the catch means per board in line with different number of boards, it means with different distance, i...
In total, 55,862 specimens of seven species of the genus Cephalcia (C. abietis, C. arvensis, C. a... more In total, 55,862 specimens of seven species of the genus Cephalcia (C. abietis, C. arvensis, C. alashanica, C. alpina, C. annulicornis, C. erythrogaster, C. masuttii) were collected using Malaise traps in spruce mountain forests from 2001 to 2006. Sex ratio was male biased as a result of used methods; males are more active and quicker. The flight activity started in the studied localities at the beginning of May or the beginning of June depending on the actual weather. C. alpina flew first, followed by C. erythrogaster and C. arvensis, the last flying species were C. alashanica and C. abietis. C. abietis was the most abundant in all localities within all years (total dominance of 93%). C. arvensis, C. alashanic and C. alpina were collected in more than hundred of specimens while C. annulicornis, C. erythrogaster and C. masuttii were collected only occasionally. Environmental variables were tested with the RDA model which proved several of them (years of 2001–2003, 2006, Český les an...
In the Czech Republic, A. nebulosus occurs in coniferous, deciduous as well as in mixed forests, ... more In the Czech Republic, A. nebulosus occurs in coniferous, deciduous as well as in mixed forests, in lowland forests and even on forest-steppe habitats. Larvae occur mainly on Picea sp., Pinus sp. and Abies sp.; adults occur on the same tree species and also on Larix sp., Quercus sp., Salix sp. and Fagus sp. Adults overwinter in the bark of several coniferous trees with thicker bark (mainly Pinus sylvestris L. and Larix decidua Mill.) where they are hidden in cracks. Woodpeckers attack such trees with masses ofA. nebulosus very intensively. In five localities with Malaise traps in the Nízký Jeseník Hills, the flight activity started at the beginning of May and ended in mid-June with the peak at the end of May and beginning of June in 2005. In 2006, the flight activity started later in mid-May and lasted to the beginning of July but was interrupted by cold and rainy weather. At higher altitudes were beetles sampled only in the first half of June in 2006. The size of males and females ...
Uploads
Papers by J. Holuša