Logic in Transition: The Logical Calculi of Hilbert (1905) and Zermelo (1908) [Abstract]
V. Peckhaus, in: Abstracts of the 9th International Congress of Logic, Methodology and Philosophy of Science, Uppsala, August 7–14, 1991, Bd. 2: General Philosophy of Science. Sections 6–9, o.O.u.J. (Uppsala), 1991, p. 158.