@article{FPM_2009_15_1_a1,
     author = {I. V. Dobrynina},
     title = {Solution of the problem of expressibility in amalgamated products of groups},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {23--30},
     publisher = {mathdoc},
     volume = {15},
     number = {1},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2009_15_1_a1/}
}