@article{bwmeta1.element.bwnjournal-article-fmv131i1p110bwm,
author = {Janusz Grabowski},
title = {Free subgroups of diffeomorphism groups},
journal = {Fundamenta Mathematicae},
volume = {131},
year = {1988},
pages = {103-121},
zbl = {0666.58011},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-fmv131i1p110bwm}
}
Grabowski, Janusz. Free subgroups of diffeomorphism groups. Fundamenta Mathematicae, Tome 131 (1988) pp. 103-121. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-fmv131i1p110bwm/