@article{RM_1996_51_6_a3,
     author = {V. V. Arestov},
     title = {Approximation of unbounded operators by bounded operators and related extremal problems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {1093--1126},
     publisher = {mathdoc},
     volume = {51},
     number = {6},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1996_51_6_a3/}
}