@article{VMUMM_1989_1_a4,
     author = {Nguen Khak Tkhan'},
     title = {An asymptotic formula for an arithmetic sum},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {21--26},
     publisher = {mathdoc},
     number = {1},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1989_1_a4/}
}