Evaluation of potential helium source rocks and helium enrichment factors in coalbed methane in the eastern margin of Ordos basin. - Chen, Yue; Tao, Shizhen; Kang, Rui; Gao, Jianrong; Yang, Yiqing; Fang, Xiang; Song, Wei; Chen, Yanyan; Liu, Xiangbai (Scientific Reports, 2026)