@article{ADM_2007_2_a7,
     author = {C. K. Gupta and N. D. Gupta and A. S. Oliynyk},
     title = {Free products of finite groups acting on regular rooted trees},
     journal = {Algebra and discrete mathematics},
     pages = {91--103},
     publisher = {mathdoc},
     number = {2},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ADM_2007_2_a7/}
}