Lai, Dehui, et al. “Minimally Invasive Percutaneous Nephrolithotomy With a Novel Vacuum-Assisted Access Sheath for Obstructive Calculous Pyonephrosis ：A Randomized Study”. Urology Journal, vol. 17, no. 05, July 2020, pp. 474-9, doi:10.22037/uj.v17i05.5577.