@article{1255380395,
author = {Goldberg, K. and Newman, M.},
title = {Pairs of matrices of order two which generate free groups},
journal = {Illinois J. Math.},
volume = {1},
number = {1},
year = {1957},
pages = { 446-448},
language = {en},
url = {http://dml.mathdoc.fr/item/1255380395}
}
Goldberg, K.; Newman, M. Pairs of matrices of order two which generate free groups. Illinois J. Math., Tome 1 (1957) no. 1, pp. 446-448. http://gdmltest.u-ga.fr/item/1255380395/