@article{DE_1972_8_12_a9,
     author = {R. S. Levitin},
     title = {A metric problem for {Frommer's} first discrimination problem},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2187--2196},
     publisher = {mathdoc},
     volume = {8},
     number = {12},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1972_8_12_a9/}
}