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2010-2020 | 
Professor Emeritus Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia  | 
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1992, 1994 | 
Visiting Research Fellow  University of Guelph, Guelph, Canada  | 
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1992-2010 | 
Full Professor Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia  | 
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1990-1992 | 
Associate Professor Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia  | 
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1989 | 
Visiting Research Fellow Department of Biosciences, University of Jammu, India  | 
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1979, 1984 | 
Visiting Research Fellow Laboratoire d'Anatomie Compare, Museum National d'Histoire Naturelle, Paris, France  | 
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1963-1990 | 
Assistant Professor Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia  | 
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1965-1967 | 
Visiting Research Fellow Institute of Anatomy, Jagiellonian University, Krakow, Poland  | 
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1961 | 
Research Assistant Institute of Biology, Slovak Academy of Sciences, Bratislava, Slovakia  |