@article{DM_1991_3_4_a2,
     author = {D. S. Gershuni},
     title = {The problem of two periodic tasks},
     journal = {Diskretnaya Matematika},
     pages = {16--23},
     year = {1991},
     volume = {3},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_1991_3_4_a2/}
}