@article{AL_1989_28_5_a1,
     author = {I. P. Bestsennyi},
     title = {Quasi-identities of finite unary algebras},
     journal = {Algebra i logika},
     pages = {493--512},
     publisher = {mathdoc},
     volume = {28},
     number = {5},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1989_28_5_a1/}
}