Authors
Tomasz Grenda
Department of Hygiene of Animal Feedingstuffs, National Veterinary Research Institute, 24-100, Pulawy, Poland
Magdalena Grabczak
Department of Hygiene of Animal Feedingstuffs, National Veterinary Research Institute, 24-100, Pulawy, Poland
Krzysztof Kwiatek
Department of Hygiene of Animal Feedingstuffs, National Veterinary Research Institute, 24-100, Pulawy, Poland
Andrzej Bober
Department of Honey Bee Diseases National Veterinary Research Institute, 24-100, Pulawy, Poland