1. Adams, J.F., Hilton, P.J.: On the chain algebra of a loop space. Commentarii math. Helvet.20,305?330 (1955)
2. Adams, J.F.: On the cobar construction, Proc. nat. Acad. Sci. U.S.A.42, 409?412 (1956)
3. Baues, H.J.: Hindernisse in dem Produkt von Suspensionen. Math. Ann.200, 11?23 (1973)
4. Baues, H.J.: Jacobi Summen f�r h�here Whitehead Produkte, preprint, Bonn (1973)
5. Coxeter, H.S.M., Moser, W.O.J.: Generators and relations for discrete groups. Berlin-Heidelberg-New York: Springer 1965