@article{AA_1999_11_5_a9,
     author = {L. Potyagailo and Sh. Wang},
     title = {On the {co-Hopficity} of $3$-manifold groups},
     journal = {Algebra i analiz},
     pages = {194--220},
     publisher = {mathdoc},
     volume = {11},
     number = {5},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1999_11_5_a9/}
}