@article{DE_1999_35_9_a1,
     author = {P. P. Zabreiko and V. V. Marchenko},
     title = {Fredholm formulas for linear integral equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1162--1170},
     publisher = {mathdoc},
     volume = {35},
     number = {9},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_9_a1/}
}