@article{MZM_1992_51_1_a15,
     author = {K. K. Pivnitskaya},
     title = {A characterization of the class of enumerable languages},
     journal = {Matemati\v{c}eskie zametki},
     pages = {134--140},
     year = {1992},
     volume = {51},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1992_51_1_a15/}
}