@article{10_4064_ap_4_2_165_182,
     author = {Z. Szmydt},
     title = {Sur l'existence d'une solution unique de certains probl\`emes pour un syst\`eme d'\'equations diff\'erentielles hyperboliques du second ordre \`a deux variables ind\'ependantes},
     journal = {Annales Polonici Mathematici},
     pages = {165--182},
     publisher = {mathdoc},
     volume = {4},
     number = {2},
     year = {1957},
     doi = {10.4064/ap-4-2-165-182},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-4-2-165-182/}
}