1. On the non-existence of elements of Hopf invariant one;Adams, J. F.;Ann. of Math. (2),1960
2. On the chain algebra of a loop space;Adams, J. F.;Comment. Math. Helv.,1956
3. On 𝐻-spaces with two non-trivial homotopy groups;Copeland, Arthur H., Jr.;Proc. Amer. Math. Soc.,1957
4. P. J. Hilton, Homotopy theory and duality (mimeographed), Cornell University, 1959.
5. On 𝐻-spaces and their homotopy groups;James, I. M.;Quart. J. Math. Oxford Ser. (2),1960