@article{FAA_1981_15_1_a10,
     author = {\'E. F. Kaplenko and V. A. Ponomarev},
     title = {Cross ratio of a nondegenerate quadruple of subspaces},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {76--77},
     publisher = {mathdoc},
     volume = {15},
     number = {1},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1981_15_1_a10/}
}