@article{1029002401, author = {Johnson, David L.}, title = {Sectional curvature and curvature normal forms.}, journal = {Michigan Math. J.}, volume = {27}, number = {1}, year = {1980}, pages = { 275-294}, language = {en}, url = {http://dml.mathdoc.fr/item/1029002401} }
Johnson, David L. Sectional curvature and curvature normal forms.. Michigan Math. J., Tome 27 (1980) no. 1, pp. 275-294. http://gdmltest.u-ga.fr/item/1029002401/