@article{ZNSL_1971_20_a1,
     author = {F. L. Varpakhovskii},
     title = {On a~class of realizable propositional formulas},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {8--23},
     publisher = {mathdoc},
     volume = {20},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_20_a1/}
}