@article{JEDP_1980____A7_0,
     author = {Gu, Chaohao},
     title = {On the mixed partial differential equations in n independent variables},
     journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {7},
     pages = {1--2},
     publisher = {Ecole polytechnique},
     year = {1980},
     language = {en},
     url = {http://www.numdam.org/item/JEDP_1980____A7_0/}
}