White, B. C. (2015) “Faecal Glucocorticoid Concentrations during ACTH Challenge Tests in Captive Grizzly Bears (Ursus arctos horribilis) and Polar Bears (Ursus maritimus)”, Journal of Zoo and Aquarium Research, 3(2), pp. 59–62. doi: 10.19227/jzar.v3i2.116.