1. Atiyah, M.F.: $$K$$ K -theory. In: Lecture Notes by D. W. Anderson, W. A. Benjamin Inc, New York-Amsterdam (1967)
2. Atiyah, M.F.: Bott periodicity and the index of elliptic operators. Quart. J. Math. Oxford Ser. (2) 19, 113–140 (1968)
3. Atiyah, M.F., Segal, G.B.: Equivariant $$K$$ K -theory and completion. J. Differ. Geom 3, 1–18 (1969)
4. Bauer, S.: Intersection forms of spin four-manifolds, e-print, arXiv:1211.7092v1
5. Bohr, C., Lee, R.: Homology cobordism and classical knot invariants. Comment. Math. Helv. 77(2), 363–382 (2002)