**
The quadratic isoperimetric inequality for mapping tori of free
group automorphisms (with M.R. Bridson). Memoirs of the AMS, ****203** (2010), no. 955.
.pdf

** Abstract **
If F is a finitely generated free group
and \phi is an automorphism of F
then F \rtimes_\phi ** Z**
satisfies a quadratic isoperimetric inequality.

(This is essentially the two papers with the same title, along with the paper
`Free-group automorphisms, train tracks and the beaded decomposition', turned into a single monograph).