Delzell, Charles N., cKreisel9s Unwinding of Artin9s Proofd, in P. Odifreddi (ed.), Kreiseliana, Wellesley, MA 1996 [Zbl 0894.03002], 1133246
V. Peckhaus, zbMATH Open, Zbl. 0876.12002 (1998).