@article{1077293729, author = {Levitt, Gilbert}, title = {Constructing free actions on $\mathbf{R}$ -trees}, journal = {Duke Math. J.}, volume = {72}, number = {1}, year = {1993}, pages = { 615-633}, language = {en}, url = {http://dml.mathdoc.fr/item/1077293729} }
Levitt, Gilbert. Constructing free actions on $\mathbf{R}$ -trees. Duke Math. J., Tome 72 (1993) no. 1, pp. 615-633. http://gdmltest.u-ga.fr/item/1077293729/