@article{106194, author = {Eva Butkovi\v cov\'a}, title = {Ultrafilters without immediate predecessors in Rudin-Frol\'\i k order}, journal = {Commentationes Mathematicae Universitatis Carolinae}, volume = {023}, year = {1982}, pages = {757-766}, zbl = {0507.03020}, mrnumber = {687570}, language = {en}, url = {http://dml.mathdoc.fr/item/106194} }
Butkovičová, Eva. Ultrafilters without immediate predecessors in Rudin-Frolík order. Commentationes Mathematicae Universitatis Carolinae, Tome 023 (1982) pp. 757-766. http://gdmltest.u-ga.fr/item/106194/
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