Dasgupta, S., V. Vats, and A. Varma. “Comparison of External and Endoscopic Endonasal Dacryocysto-Rhinostomy: A Hospital Based Retrospective Study”. International Journal of Research in Medical Sciences, vol. 4, no. 7, Jan. 2017, pp. 2822-9, doi:10.18203/2320-6012.ijrms20161958.