Mohamed A. Abu El-Hamd, Abdelslam M. Metwally, Zahya R. Ghallab, Wael A. El-Hamady and Mohamed A. El-karamany, 2023. Improving Fertility in Friesian Cows by Synchronization of Fixed Time Insemination. Pakistan J. Zool., 55: 2325-2331. 
DOI: https://dx.doi.org/10.17582/journal.pjz/20211115171134