@article{DAN_1988_299_6_a7,
     author = {A. M. Nakhushev and M. S. Salakhitdinov},
     title = {The law of composition of operators for fractional},
     journal = {Doklady Akademii Nauk},
     pages = {1313--1316},
     publisher = {mathdoc},
     volume = {299},
     number = {6},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_299_6_a7/}
}