@article{AL_1970_9_3_a4,
     author = {V. P. Klassen},
     title = {The occurrence problem for a certain class of groups},
     journal = {Algebra i logika},
     pages = {306--312},
     publisher = {mathdoc},
     volume = {9},
     number = {3},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1970_9_3_a4/}
}