@article{1102806637,
author = {Brenner, J. L. and Charnow, A.},
title = {Free semigroups of $2\times 2$ matrices.},
journal = {Pacific J. Math.},
volume = {79},
number = {2},
year = {1978},
pages = { 57-69},
language = {en},
url = {http://dml.mathdoc.fr/item/1102806637}
}
Brenner, J. L.; Charnow, A. Free semigroups of $2\times 2$ matrices.. Pacific J. Math., Tome 79 (1978) no. 2, pp. 57-69. http://gdmltest.u-ga.fr/item/1102806637/