J. de Bakker/J. van Leeuwen (ed.): Automata, languages and programming. Springer LN Comp. Sci. 84 (1980). C. Bennett: Logical reversibility of computation. IBM J. Res. Devel. 17 (1973), 525-532. Y. Lecerf: Machines de Turing reversibles. Recursive insolubilite' en n \in N de l'equation u=\theta^n u, ou' \theta est un isomorphisme de codes. CR Ac. Fran. Sci. 257 (1963), 2597-2600. T. Toffoli: Reversible computing. In de Bakker/van Leeuwen 1980, 632-644.