1. Heinz Bachmann: Transfinite Zahlen. Springer, Berlin (1967)
2. John L. Bell, Alan B. Slomson: Models and Ultraproducts: An Introduction. North-Holland, Amsterdam (1969)
3. Paul Bernays: Sur le platonisme dans les mathématiques. Enseign. Math. 34, 52–69 (1935) (see [7]/[6] for a translation into English/German)
4. Paul Bernays: A system of axiomatic set theory. III: Infinity and enumerability. Analysis. J. Symb. Log. 7, 65–89 (1942)
5. Studies in Logic and the Foundations of Mathematics;Paul Bernays,1968