仇庆久. ON PARTIAL HYPOELLIPTICITY OF FIRST ORDER FUCHSIAN EVOLUTION OPERATORS[J]. 数学物理学报(英文版), 1983, 3(1): 13-26.
Qiu Qingjiu. ON PARTIAL HYPOELLIPTICITY OF FIRST ORDER FUCHSIAN EVOLUTION OPERATORS[J]. Acta mathematica scientia,Series B, 1983, 3(1): 13-26.