Yadav, M. C., J. S. Walton, and K. E. Leslie. 1988. “Reproductive Endocrinology of the Cow: Part 1: Endocrinology of the Estrous Cycle”. The Bovine Practitioner, no. 23 (November):4-10. https://doi.org/10.21423/bovine-vol0no23p4-10.