Supine percutaneous nephrolitotripsy in septuagenarian and octogenarian patients: outcomes of a case-control study - Torricelli, Fabio C. M.; Ogawa, Guilherme K. M.; Vicentini, Fabio C.; Marchini, Giovanni S.; Danilovic, Alexandre; Srougi, Miguel; Nahas, William Carlos; Mazzucchi, Eduardo (Canadian journal of urology, 2018)