1. Some almost polyhedral wild arcs;Alford, W. R.;Duke Math. J.,1963
2. Penetration indices and applications;Ball, B. J.,1962
3. On infinitely generated modules;Brody, E. J.;Quart. J. Math. Oxford Ser. (2),1960
4. On the van Kampen theorem;Crowell, Richard H.;Pacific J. Math.,1959
5. Corresponding group and module sequences;Crowell, R. H.;Nagoya Math. J.,1961