@article{INTG_1989_21_a3,
     author = {V. B. Marenich and V. A. Toponogov},
     title = {Open manifolds of nonnegative curvature},
     journal = {Itogi Nauki i Tekhniki. Seriya Problemy Geometrii. Trudy Geometricheskogo Seminara},
     pages = {67--91},
     publisher = {mathdoc},
     volume = {21},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTG_1989_21_a3/}
}