@article{MZM_1986_39_2_a11,
     author = {S. S. Marchenkov},
     title = {Existence of superposition bases in countable primitively recursively closed classes},
     journal = {Matemati\v{c}eskie zametki},
     pages = {268--276},
     publisher = {mathdoc},
     volume = {39},
     number = {2},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1986_39_2_a11/}
}