@article{DAN_1989_305_5_a7,
     author = {V. I. Sumin},
     title = {Volterra functional-operator equations in the theory of the},
     journal = {Doklady Akademii Nauk},
     pages = {1056--1059},
     publisher = {mathdoc},
     volume = {305},
     number = {5},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_305_5_a7/}
}