@article{AL_1991_30_5_a6,
     author = {D. G. Khramtsov},
     title = {Finite graphs of groups with isomorphic fundamental groups},
     journal = {Algebra i logika},
     pages = {595--623},
     year = {1991},
     volume = {30},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1991_30_5_a6/}
}