WOJTUSIK, J.; BRANDICOURT, I.; RICE, W.; ROTH, T. Reproductive cycle and pregnancy monitoring in the common hippopotamus (Hippopotamus amphibius) through salivary steroid analyses and trans-abdominal ultrasonography. . Journal of Zoo and Aquarium Research, [S. l.], v. 8, n. 3, p. 181-187, 2020. DOI: 10.19227/jzar.v8i3.494. Disponível em: https://jzar.org/jzar/article/view/494. Acesso em: 23 sep. 2020.