Kershaw, C. M., Khalid, M., McGowan, M. R., Ingram, K., Leethongdee, S., Wax, G., & Scaramuzzi, R. J. The anatomy of the sheep cervix and its influence on the transcervical passage of an inseminating pipette into the uterine lumen. THERIOGENOLOGY, 64(5), 1225-1235. https://doi.org/10.1016/j.theriogenology.2005.02.017