@article{AL_1990_29_1_a3,
     author = {A. M. Nurakunov},
     title = {Quasivarieties of algebras with definable principal},
     journal = {Algebra i logika},
     pages = {35--46},
     publisher = {mathdoc},
     volume = {29},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1990_29_1_a3/}
}