@article{INTG_1991_23_a4,
     author = {I. Ivanova-Karatopraklieva and I. Kh. Sabitov},
     title = {Deformation of {surfaces.~I}},
     journal = {Itogi Nauki i Tekhniki. Seriya Problemy Geometrii. Trudy Geometricheskogo Seminara},
     pages = {131--184},
     publisher = {mathdoc},
     volume = {23},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTG_1991_23_a4/}
}