Development and validation of a preoperative nomogram for predicting positive surgical margins after laparoscopic radical prostatectomy oleh Xiao-Jun Tian, Zhao-Lun Wang, Geng Li, Shuang-Jie Cao, Hao-Ran Cui, Zong-Han Li, Zhuo Liu, Bo-Lun Li, Lu-Lin Ma, Shen-Rong Zhuang, Qi-Yan Xiao, Xin Chen