Coprenican Letters
, 1 Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, Department of Ecology and Environmental Protection, Skłodowska-Curie St. 9, PL 85-094 Bydgoszcz, Poland, phone (00 48 52) 585 38 05, fax (00 48 52) 585 38 07, Poland