@article{MO_2020_2_a6,
     author = {E. G. Smoljanova},
     title = {Vector-geometric interpretation of an invariant of a fractional-quadratic function},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {48--54},
     year = {2020},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2020_2_a6/}
}