@article{PM_1998_1998_1_a16,
     author = {Koubi, Malik},
     title = {Tasas de crecimiento exponencial para grupos libres.},
     journal = {Publicacions matem\`atiques},
     pages = {499-507},
     publisher = {mathdoc},
     volume = {42},
     number = {2},
     year = {1998},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PM_1998_1998_1_a16/}
}