@article{IM_1995__120_2_144286,
     author = {E. Rips and Z. Sela},
     title = {Canonical representatives and equations in hyperbolic groups.},
     journal = {Inventiones mathematicae},
     pages = {489--512},
     publisher = {mathdoc},
     volume = {120},
     number = {2},
     year = {1995},
     zbl = {0845.57002},
     url = {http://geodesic.mathdoc.fr/item/IM_1995__120_2_144286/}
}