@article{RM_1992_47_1_a10,
     author = {S. M. Natanzon},
     title = {A~topological classification of a~pair of spinor forms on surfaces},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {265--266},
     publisher = {mathdoc},
     volume = {47},
     number = {1},
     year = {1992},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1992_47_1_a10/}
}