S. R. KC, B. R. Timilsina, H. P. Upadhyay, G. Devkota, R. Shah, and N. Lamichanne, “Sildenafil is Safe and Effective for the Treatment of Lower Ureteric Stone with no Major Side Effect”, Birat J. Health Sci., vol. 3, no. 3, pp. 560–564, Jan. 2019.