Efficacy and safety of ultrasound-guided percutaneous nephrolithotomy for kidney calculi patients with ankylosing spondylitis: a retrospective single center analysis - Xia, Mingrui; Hong, Yang; An, Lizhe; Xiong, Liulin; Huang, Xiaobo; Xu, Qingquan (Annals of Palliative Medicine, 2021)