Cheng, H.H.ChengWu, TtTtWuTSUNG-TSONG WU2020-04-282020-04-2819710556-2821https://scholars.lib.ntu.edu.tw/handle/123456789/487158Theory of Pionizationjournal article10.1103/PhysRevD.3.2195WOS:A1971J373400026