On the Homotopy Classification of 2-Complexes. Texas NExT Research Session, Meeting of the Texas Section of the MAA, Corpus Christi, TX (April 2004).

Abstract
The homotopy classification for 2-complexes is complete only when the fundamental group is finite or free. Martin Dunwoody, however, studied homotopy types of 2-complexes where the fundamental group is the trefoil group, and was able to construct homotopy inequivalent 2-complexes one level above the minimal possible Euler characteristic. We take a new look at Dunwoody's work and present generalizations to other groups of cohomological dimension 2.