@article{1103857228, author = {Ludwig, Garry and Scanlan, Gerry}, title = {Classification of the Ricci tensor}, journal = {Comm. Math. Phys.}, volume = {20}, number = {1}, year = {1971}, pages = { 291-300}, language = {en}, url = {http://dml.mathdoc.fr/item/1103857228} }
Ludwig, Garry; Scanlan, Gerry. Classification of the Ricci tensor. Comm. Math. Phys., Tome 20 (1971) no. 1, pp. 291-300. http://gdmltest.u-ga.fr/item/1103857228/