1. Partition theorems and ultrafilters;Baumgartner;Trans. Amer. Math. Soc.,1978
2. The Rudin-Keisler ordering of P-points;Blass;Trans. Amer. Math. Soc.,1973
3. Ultrafilter mappings and their Dedeking cuts;Blass;Trans. Amer. Math. Soc.,1974
4. Some initial segments of the Rudin-Keisler ordering;Blass;J. Symbolic Logic,1981
5. Selective ultrafilters and homogeneity;Blass;Ann. Pure Appl. Logic,1988