... observed in Poland by manyscientists (Borowiec et al. 199 2, Korniak 199 2, Fija kowski et al. 199 2, Sendek 199 2,Trzci ska-Tacik 199 2, Warcholi ska 199 2, Stupnicka-Rodzynkiewicz et al. 199 2a, 199 2b). ... unpublished data, Ho dy ski 199 1,Kutyna 198 8, Latowski et al. 197 9, Labza 199 4, Skrzyczy ska 199 8, Skrzyczy skaand Skrajna 199 , Szotkowski 197 3, Warcholinska 197 6, 198 3, 199 7, Wika 198 6).WWWWaaaarrrrsssszzzzaaaawwwwaaaa374371320 193 1 79 1762633613482772 19 258ol´nl´n´n´n´n´n ... al. 198 4, Mills and Alley 197 3, Tischler 196 5, Braman and Pendley 199 3, Tucker and Heath 199 4, Goh Hyun Gwan et al. 199 5, Lopez Fando and Bello 199 5, Edwards and Bohlen 199 6, Hu Feng et al. 199 7,...