@article{IVM_1991_9_a13,
     author = {L. F. Korkina and M. A. Rekant},
     title = {Fractional powers of a~class of operators},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {81--83},
     year = {1991},
     number = {9},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1991_9_a13/}
}