Mendoza, Jonathan, Danison Pagtakhan, and Jose Benito Abraham. 2020. “Comparative Analysis of the Efficacy and Safety Profile of Upper Calyceal Versus Lower Calyceal Access in the Percutaneous Nephrolithotomy (PCNL): A Retrospective Cross-Sectional Study”. Philippine Journal of Urology 27 (1):6-10. https://pjuonline.com/index.php/pju/article/view/35.