@article{VMUMM_1983_6_a7,
     author = {P. L. Ul'yanov},
     title = {Uniqueness of series in a {Haar} system with monotone coefficients},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {63--73},
     year = {1983},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1983_6_a7/}
}