@article{GDZPPN002346915,
title = {Planes of Curvature in Riemannian Spaces.},
journal = {Mathematica Scandinavica},
volume = {11},
year = {1962},
pages = {5-21},
zbl = {0121.38601},
url = {http://dml.mathdoc.fr/item/GDZPPN002346915}
}
Eriksson, Folke. Planes of Curvature in Riemannian Spaces.. Mathematica Scandinavica, Tome 11 (1962) pp. 5-21. http://gdmltest.u-ga.fr/item/GDZPPN002346915/