1. Section of Toxicology, National Veterinary Institute, POB 8156 Dep., N-0033 Oslo, Norway
2. Department of Reproduction and Forensic Medicine, Norwegian School of Veterinary Science, POB 8146 Dep., N-0033 Oslo, Norway
3. Section of Wildlife Diseases, National Veterinary Institute, POB 8156 Dep., N-0033 Oslo, Norway
4. Department of Arctic Veterinary Medicine, Norwegian School of Veterinary Science, N-9005 Tromsø, Norway