@article{MO_2020_1_a4,
     author = {Al. A. Privalov},
     title = {On some properties and criterions of a parallelogram},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {36--45},
     year = {2020},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2020_1_a4/}
}