Alkar A., Tibary A., Wenz J.R., Nebel R., and Kasimanickam R. 2011. “Effect Of Presynchronization With GnRH 7 Days Prior To Resynchronization With CO-Synch On Pregnancy Wastage In Lactating Dairy Cows”. Clinical Theriogenology 2 (4):467-71. https://clinicaltheriogenology.net/index.php/CT/article/view/10146.