@article{MZM_1967_1_4_a1,
     author = {S. V. Bochkarev},
     title = {Unconditional bases},
     journal = {Matemati\v{c}eskie zametki},
     pages = {391--398},
     publisher = {mathdoc},
     volume = {1},
     number = {4},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1967_1_4_a1/}
}