@article{1102811918, author = {Burns, John T.}, title = {Curvature functions on Lorentz $2$-manifolds.}, journal = {Pacific J. Math.}, volume = {73}, number = {2}, year = {1977}, pages = { 325-335}, language = {en}, url = {http://dml.mathdoc.fr/item/1102811918} }
Burns, John T. Curvature functions on Lorentz $2$-manifolds.. Pacific J. Math., Tome 73 (1977) no. 2, pp. 325-335. http://gdmltest.u-ga.fr/item/1102811918/