Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{MOMA_1997__124_4_178785, author = {J.S. Cassel and Zhanyuan Hou}, title = {Initial {Value} {Problem} for {Mixed-Type} {Differential} {Equations.}}, journal = {Monatshefte f\"ur Mathematik}, pages = {133--146}, publisher = {mathdoc}, volume = {124}, number = {4}, year = {1997}, zbl = {0884.34073}, url = {http://geodesic.mathdoc.fr/item/MOMA_1997__124_4_178785/} }
J.S. Cassel; Zhanyuan Hou. Initial Value Problem for Mixed-Type Differential Equations.. Monatshefte für Mathematik, Tome 124 (1997) no. 4, pp. 133-146. http://geodesic.mathdoc.fr/item/MOMA_1997__124_4_178785/