@article{GDZPPN002542307, title = {On commuting elemts of groups acting on trees}, journal = {Revista colombiana de matematicas}, volume = {27}, year = {1993}, pages = {293-301}, zbl = {0813.20025}, url = {http://dml.mathdoc.fr/item/GDZPPN002542307} }
Mahmud, R. M. S. On commuting elemts of groups acting on trees. Revista colombiana de matematicas, Tome 27 (1993) pp. 293-301. http://gdmltest.u-ga.fr/item/GDZPPN002542307/