I. Horrell, P. A’Ness et al. (2000): Nose-rings influence feeding efficiency in pigs. Animal Science, 71(2), 259–264 doi:10.1017/S1357729800055090
H. Mejer, S. Wendt, L. E. Thomsen et al. (2000): Nose-rings and transmission of helminth parasites in outdoor pigs. Acta Veterinari Scandinavica 2000; 41(2):153-65. PMID 10965566; PMC 7996443 (freier Volltext). doi:10.1186/BF03549647
H. Mejer, S. Wendt, L. E. Thomsen et al. (2000): Nose-rings and transmission of helminth parasites in outdoor pigs. Acta Veterinari Scandinavica 2000; 41(2):153-65. PMID 10965566; PMC 7996443 (freier Volltext). doi:10.1186/BF03549647