@article{RM_1963_18_3_a7,
     author = {A. Yu. Levin and Yu. I. Petunin},
     title = {Some problems related to the concept of orthogonality in {a~Banach} space},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     year = {1963},
     volume = {18},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1963_18_3_a7/}
}