1. Resolution of the Government of the Republic of Kazakhstan No. 1469 of December 31,
2004—On Establishment of the Rules for Granting Permission to Use Animals. https://online.zakon.kz/document/?doc_id=1052607# pos=0;0
2. Order of the Minister of Agriculture of the Republic of Kazakhstan No. 652 of November 10,
2004—On Approval of the Rules for Using Animals, Except Rare and Endangered Species, for Scientific, Cultural-Educational, Up-Bringing, and Esthetic Purposes, as well as for Creation of Zoological Collections. http://adilet.zan.kz/rus/origins/ V14F0010168
3. Endocrinology;D.J. St. Aubin,2001
4. Boily, P., Metabolic and hormonal changes during the molt of captive gray seals (Halichoerus grypus), Am. J. Physiol., 1996, vol. 270, pp. R1051−R1058.
5. Brouwer, A., Reijnders, P.J.H., and Koeman, J.H., Polychlorinated biphenyl (PCB) induces vitamin A deficiency in the common seal (Phoca vitulina), Aquat. Toxicol., 1989, vol. 15, pp. 99−106.