@article{MAN_1968__178_161744,
     author = {J. PERSSON},
     title = {New {Proofs} and {Generalizations} of {Two} {Theorems} by {Lednev} for {Goursat} {Problems.}},
     journal = {Mathematische Annalen},
     pages = {184--208},
     publisher = {mathdoc},
     volume = {178},
     year = {1968},
     zbl = {0159.14701},
     url = {http://geodesic.mathdoc.fr/item/MAN_1968__178_161744/}
}