@article{DAN_1976_230_2_a8,
     author = {A. G. Ramm},
     title = {Investigation of a class of integral equations},
     journal = {Doklady Akademii Nauk},
     pages = {283--286},
     year = {1976},
     volume = {230},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1976_230_2_a8/}
}