Al-Dulaimi, Makki Khalaf Hussain. “The Effect of Age in the Shape of the Spermatozoa Frozen Friesian Bulls”. JOURNAL OF UNIVERSITY OF BABYLON for Pure and Applied Sciences 26, no. 10 (December 21, 2018): 36 - 40. Accessed January 24, 2020. https://journalofbabylon.com/index.php/JUBPAS/article/view/1837.