@article{IM2_1967_1_1_a1,
     author = {E. M. Nikishin},
     title = {Convergence of certain functional series},
     journal = {Izvestiya. Mathematics},
     pages = {13--23},
     year = {1967},
     volume = {1},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1967_1_1_a1/}
}