@article{SM_1999_190_8_a0,
     author = {V. S. Guba and M. V. Sapir},
     title = {On subgroups of {R.~Thompson's} group~$F$ and other diagram groups},
     journal = {Sbornik. Mathematics},
     pages = {1077--1130},
     publisher = {mathdoc},
     volume = {190},
     number = {8},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1999_190_8_a0/}
}