@article{VMUMM_1999_6_a6,
     author = {V. V. Kostin and V. A. Skvortsov},
     title = {Martingale sequences in the theory of orthogonal series},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {50--53},
     year = {1999},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1999_6_a6/}
}