Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1970_193_3_a14, author = {V. N. Shuhman}, title = {The {Cauchy} problem for not strictly hyperbolic equations}, journal = {Doklady Akademii Nauk}, pages = {551--553}, publisher = {mathdoc}, volume = {193}, number = {3}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1970_193_3_a14/} }
V. N. Shuhman. The Cauchy problem for not strictly hyperbolic equations. Doklady Akademii Nauk, Tome 193 (1970) no. 3, pp. 551-553. http://geodesic.mathdoc.fr/item/DAN_1970_193_3_a14/