@article{GDZPPN002065401, title = {Values of pseudoriemannian sectional cuvature.}, journal = {Commentarii mathematici Helvetici}, volume = {59}, year = {1984}, pages = {319-332}, zbl = {0573.53014}, url = {http://dml.mathdoc.fr/item/GDZPPN002065401} }
Beem, John K.; Parker, Philipp E. Values of pseudoriemannian sectional cuvature.. Commentarii mathematici Helvetici, Tome 59 (1984) pp. 319-332. http://gdmltest.u-ga.fr/item/GDZPPN002065401/