1. An inverse function theorem for free groups;Birman, Joan S.;Proc. Amer. Math. Soc.,1973
2. On the two-dimensional realisability of chain complexes;Cockcroft, W. H.;J. London Math. Soc. (2),1975
3. Relation modules;Dunwoody, M. J.;Bull. London Math. Soc.,1972
4. M. N. Dyer, Spaces dominated by finite two-dimensional CW-complexes (to appear).
5. W. Magnus, A. Karrass and D. Solitar, Combinatorial group theory, Pure and Appl. Math., vol. 13, Interscience, New York, 1966.