@article{GDZPPN002300109,
title = {New Proofs and Generalizations of Two Theorems by Lednev for Goursat Problems.},
journal = {Mathematische Annalen},
volume = {179},
year = {1968},
pages = {184-208},
zbl = {0159.14701},
url = {http://dml.mathdoc.fr/item/GDZPPN002300109}
}
PERSSON, J. New Proofs and Generalizations of Two Theorems by Lednev for Goursat Problems.. Mathematische Annalen, Tome 179 (1968) pp. 184-208. http://gdmltest.u-ga.fr/item/GDZPPN002300109/