Effect of enrichments on behavioural reaction norms of two captive polar bears (Ursus maritimus) in Aalborg Zoo, Denmark. Genet. Biodiv. J [انترنت]. 1 مايو، 2020 [وثق 22 سبتمبر، 2025];4(2):61-72. موجود في: https://journals.univ-tlemcen.dz/GABJ/index.php/GABJ/article/view/98