@article{ASNSP_1972_3_26_2_299_0,
     author = {Andreotti, Aldo and Denson Hill, C.},
     title = {Complex characteristic coordinates and tangential {Cauchy-Riemann} equations},
     journal = {Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche},
     pages = {299--324},
     publisher = {Scuola normale superiore},
     volume = {Ser. 3, 26},
     number = {2},
     year = {1972},
     mrnumber = {460724},
     zbl = {0256.32006},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1972_3_26_2_299_0/}
}