Dahl, F.M. , Hanse, H.H. , Vorup, L.D. , Jensen, L. Østergaard ., Spyridopoulos, P.S. , Jensen, T.H. , Pertoldi, C. , Alstrup, A.K.O. and Pagh, S. 2020. Effect of enrichments on behavioural reaction norms of two captive polar bears (Ursus maritimus) in Aalborg Zoo, Denmark. Genetics & Biodiversity Journal . 4, 2 (May 2020), 61–72. DOI:https://doi.org/10.46325/gabj.v4i2.98.