@article{10_4064_cm_37_1_105_111,
     author = {Z. Olszak},
     title = {On totally umbilical surfaces in some {Riemannian} spaces},
     journal = {Colloquium Mathematicum},
     pages = {105--111},
     publisher = {mathdoc},
     volume = {37},
     number = {1},
     year = {1971},
     doi = {10.4064/cm-37-1-105-111},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-37-1-105-111/}
}