Interobserver variability in target volume delineation in definitive radiotherapy for thoracic esophageal cancer: a multi-center study from China. - Chang, Xiao; Deng, Wei; Wang, Xin; Zhou, Zongmei; Yang, Jun; Guo, Wenling; Liu, Miaoling; Qi, Xiaolu; Li, Ling; Zhang, Kaixian; Zhang, Min; Shi, Yonggang; et al. (Radiation Oncology, 2021)