Mendoza, J., Pagtakhan, D. and Abraham, J.B. 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 (Feb. 2020), 6-10.