@article{10_4064_cm_58_2_259_268,
     author = {Ryszard Deszcz and Wies{\l}aw Grycak},
     title = {On certain curvature conditions on {Riemannian} manifolds},
     journal = {Colloquium Mathematicum},
     pages = {259--268},
     publisher = {mathdoc},
     volume = {58},
     number = {2},
     year = {1989},
     doi = {10.4064/cm-58-2-259-268},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-58-2-259-268/}
}