@article{INTF_1990_58_a0,
     author = {D. J. Collins and H. Zieschang},
     title = {Combinatorial theory of groups, and fundamental groups},
     journal = {Itogi Nauki i Tekhniki. Seriya Sovremennye Problemy Matematiki. Fundamental'nye Napravleniya },
     pages = {5--190},
     publisher = {mathdoc},
     volume = {58},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTF_1990_58_a0/}
}