@article{INTG_1989_21_a2,
     author = {I. G. Nikolaev},
     title = {The closure of the set of classical {Riemannian} spaces},
     journal = {Itogi Nauki i Tekhniki. Seriya Problemy Geometrii. Trudy Geometricheskogo Seminara},
     pages = {43--66},
     publisher = {mathdoc},
     volume = {21},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTG_1989_21_a2/}
}