Voir la notice de l'article provenant de la source Novi sad journal of mathematics website
@article{NSJOM_1992_22_1a_13, author = {Konopka Czes{\l}aw,}, title = {On extrinsic spheres in a locally product riemannian manifold}, journal = {Novi Sad Journal of Mathematics}, pages = {141-148}, publisher = {mathdoc}, volume = {22}, number = {1}, year = {1992}, url = {http://geodesic.mathdoc.fr/item/NSJOM_1992_22_1a_13/} }
Konopka Czesław,. On extrinsic spheres in a locally product riemannian manifold. Novi Sad Journal of Mathematics, Tome 22 (1992) no. 1. http://geodesic.mathdoc.fr/item/NSJOM_1992_22_1a_13/