@article{1103859333, author = {Hawking, S. W.}, title = {A variational principle for black holes}, journal = {Comm. Math. Phys.}, volume = {29}, number = {1}, year = {1973}, pages = { 323-334}, language = {en}, url = {http://dml.mathdoc.fr/item/1103859333} }
Hawking, S. W. A variational principle for black holes. Comm. Math. Phys., Tome 29 (1973) no. 1, pp. 323-334. http://gdmltest.u-ga.fr/item/1103859333/