From McKeown to Ivor Lewis, the learning curve for thoracic lymphadenectomy over the first 100 robotic esophagectomy cases: a retrospective study - Zhuo, Ze-Guo; Li, Gang; Song, Tie-Niu; Alai, Gu-Ha; Shen, Xu; Wang, Yun; Lin, Yi-Dan (Journal of Thoracic Disease; Vol 13, No 3 (March 28, 2021): Journal of Thoracic Disease, 2021)