[B1] A. BLASS: Orderings of Ultrafilters. Thesis, Harvard University, Cambridge, Mass., 1970.
[B2] A. BLASS:
The Rudin-Keisler ordering of P-points. Trans. Amer. Math. Soc. 179 (1973), 145-166.
MR 0354350 |
Zbl 0269.02025
[S-V] A. SOCHOR P. VOPĚNKA:
Endomorphic Universes and their standard extensions. Comment. Math. Univ. Carolinae 20 (1979), 605-629.
MR 0555178
[T] A. TZOUVARAS:
Minimal ultrafilters and maximal endomorphic universes. Comment. Math. Univ. Carolinae 26 (1985), 719-726.
MR 0831807 |
Zbl 0587.03040