@article{DE_1976_12_7_a25,
     author = {N. P. Erugin},
     title = {Nikola{\v\i} {Evgrafovi{\v{c}}} {Ko{\v{c}}in} (on the occasion of the 75th anniversary of his birth)},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1327--1331},
     publisher = {mathdoc},
     volume = {12},
     number = {7},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_7_a25/}
}