@article{GDZPPN001169106,
title = {A Simple, Global, Complementary Variational Principle.},
journal = {Numerische Mathematik},
volume = {15},
year = {1970},
pages = {52-57},
url = {http://dml.mathdoc.fr/item/GDZPPN001169106}
}
DANIEL, J.W. A Simple, Global, Complementary Variational Principle.. Numerische Mathematik, Tome 15 (1970) pp. 52-57. http://gdmltest.u-ga.fr/item/GDZPPN001169106/