@article{IM2_1969_3_6_a6,
     author = {N. K. Nikol'skii},
     title = {Complete extensions of {Volterra} operators},
     journal = {Izvestiya. Mathematics},
     pages = {1271--1276},
     year = {1969},
     volume = {3},
     number = {6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1969_3_6_a6/}
}