@article{GDZPPN001173863,
title = {On Patched Variational Principles with Application to Elliptic and Mixed Elliptic-Hyperbolic Problems.},
journal = {Numerische Mathematik},
volume = {28},
year = {1977},
pages = {259-272},
zbl = {0348.65097},
url = {http://dml.mathdoc.fr/item/GDZPPN001173863}
}
Fix, G.J.; Gurtin, M.E. On Patched Variational Principles with Application to Elliptic and Mixed Elliptic-Hyperbolic Problems.. Numerische Mathematik, Tome 28 (1977) pp. 259-272. http://gdmltest.u-ga.fr/item/GDZPPN001173863/