1. K-Theory of Forms;Bak,1981
2. Homotopy ringoids and homotopy groups;Barratt;Quart. J. Math. Oxford Ser.,1954
3. Relative Homotopiegruppen bei Abbildungskegeln;Baues;Compositio Math.,1976
4. Obstruction Theory;Baues,1977
5. Commutator Calculus and Groups of Homotopy Classes;Baues,1981