@article{GDZPPN00238700X,
title = {On Sonic Limit Lines in the Hodograph Method.},
journal = {Mathematische Zeitschrift},
volume = {67},
year = {1957},
pages = {229-237},
zbl = {0083.41103},
url = {http://dml.mathdoc.fr/item/GDZPPN00238700X}
}
Ludford, G.S.S.; Schot, S.H. On Sonic Limit Lines in the Hodograph Method.. Mathematische Zeitschrift, Tome 67 (1957) pp. 229-237. http://gdmltest.u-ga.fr/item/GDZPPN00238700X/