@article{DAN_1968_178_3_a5,
     author = {I. Il'yasov},
     title = {The summation of composite functions of {Euler's} function},
     journal = {Doklady Akademii Nauk},
     pages = {529--532},
     publisher = {mathdoc},
     volume = {178},
     number = {3},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_178_3_a5/}
}