Imam, A. M. A. .; Sabra, A. M. A.; Nasr, A. M. A. A.; Fetih, A. N. H. Efficacy of Combined Letrozole-Metformin in Comparison With Letrozole Only in Clomiphene Resistant Infertile Women With Polycystic Ovarian Syndrome: A Randomized Controlled Trial. Int. J. of Health Sci. 2022, 6, 1062-1071.