Christensen, A. C. M., Haresign, W., & Khalid, M. (2014). Progesterone exposure of seasonally anoestrous ewes alters the expression of angiogenic growth factors in preovulatory follicles. Theriogenology, 81(2), 358-367. https://doi.org/10.1016/j.theriogenology.2013.10.005