@article{IVM_2018_1_a3, author = {F. N. Garif'yanov}, title = {On summary equation generated by a quadrangle}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {27--33}, publisher = {mathdoc}, number = {1}, year = {2018}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_2018_1_a3/} }