@article{ZNSL_1971_20_a7,
     author = {V. A. Lifshits},
     title = {On investigation of constructive functions by the fillings method},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {67--79},
     publisher = {mathdoc},
     volume = {20},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_20_a7/}
}