@article{GDZPPN00222237X,
title = {Discontinous Solutions of a Nonlinear Hyperbolic Equation with Unilateral Constraints.},
journal = {Manuscripta mathematica},
volume = {29},
year = {1979},
pages = {323-352},
zbl = {0419.35061},
url = {http://dml.mathdoc.fr/item/GDZPPN00222237X}
}
Citrini, Claudio. Discontinous Solutions of a Nonlinear Hyperbolic Equation with Unilateral Constraints.. Manuscripta mathematica, Tome 29 (1979) pp. 323-352. http://gdmltest.u-ga.fr/item/GDZPPN00222237X/