Feigenbaum, M.J.: Phys. Lett.74A, 375–378 (1979)
Feigenbaum, M.J.: Commun. Math. Phys.77, 65–86 (1980)
Nauenberg, M., Rudnick, J.: Universality and the power spectrum at the onset of chaos. Preprint UCSC (1981)
Campanino, M., Epstein, H., Ruelle, D.: On Feigenbaum's functional equation ϕ(ϕ(λx))=−λϕ(x). Preprint IHES (1980), Campanino, M., Epstein, H.: On the existence of Feigenbaum's fixed point. Commun. Math. Phys.79, 261–302 (1981)
Lanford, O.E.: A computer assisted proof of the Feigenbaum conjectures Preprint IHES 1981
Feigenbaum, M.: Qualitative universality for a class of nonlinear transformations. J. Stat. Phys.19, 25–52 (1978);21, 669–706 (1979)