Kairies, H.-H. “On a Banach Space Automorphism and Its Connections to Functional Equations and Continuous Nowhere Differentiable Functions”. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, vol. 1, July 2001, pp. 39-48, https://studmath.uken.krakow.pl/article/view/13515.