@article{GDZPPN002485737, title = {On 3-Dimensional Riemannian ...-Spaces.}, journal = {Monatshefte f\"ur Mathematik}, volume = {104}, year = {1987}, pages = {303-320}, zbl = {0632.53040}, url = {http://dml.mathdoc.fr/item/GDZPPN002485737} }
Kowalski, Oldrich; Sekizawa, Masami. On 3-Dimensional Riemannian ...-Spaces.. Monatshefte für Mathematik, Tome 104 (1987) pp. 303-320. http://gdmltest.u-ga.fr/item/GDZPPN002485737/