@article{01863412, title = {Maximal index automorphisms of free groups with no attracting fixed points on the boundary are Dehn twists.}, journal = {Geometry \& Topology}, volume = {6}, year = {2002}, pages = {897-919}, doi = {10.2140/agt.2002.2.897}, zbl = {1047.20021}, language = {en}, url = {http://dml.mathdoc.fr/item/01863412} }
Martino, Armando. Maximal index automorphisms of free groups with no attracting fixed points on the boundary are Dehn twists.. Geometry & Topology, Tome 6 (2002) pp. 897-919. doi : 10.2140/agt.2002.2.897. http://gdmltest.u-ga.fr/item/01863412/