@article{1183544335, author = {Protter, Murray H.}, title = {Review: M. M. Smirnov, Equations of mixed type}, journal = {Bull. Amer. Math. Soc. (N.S.)}, volume = {1}, number = {2}, year = {1979}, pages = { 534-538}, language = {en}, url = {http://dml.mathdoc.fr/item/1183544335} }
Protter, Murray H. Review: M. M. Smirnov, Equations of mixed type. Bull. Amer. Math. Soc. (N.S.), Tome 1 (1979) no. 2, pp. 534-538. http://gdmltest.u-ga.fr/item/1183544335/