Ozgur, Berat Cem, Faruk Gonenc, and Ahmet H Yazicioglu. “Sildenafil or Vardenafil Nonresponders’ Erectile Response to Tadalafil”. Urology Journal 6, no. 4 (December 17, 2009): 267–271. Accessed July 29, 2026. https://ojs3.sbmu.ac.ir/urolj/index.php/uj/article/view/502.