@article{IVM_1972_1_a3,
     author = {Z. F. Karpycheva},
     title = {A~certain property of the exponential integral function and its repeated integrals},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {33--41},
     publisher = {mathdoc},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1972_1_a3/}
}