1. Every extremally disconnected bicompactum of weight c is inhomogeneous;Arhangel'skiĭ;Doklady Akad. Nauk SSSR,1967
2. Ultrafilters on a countable set;Booth;Annals of Math. Logic,1970
3. Deux classes remarquables d'ultrafiltres sur N;Choquet;Bull. Sci. Math.,1968
4. Ultrafilters: some old and some new results;Comfort;Bull. Amer. Math. Soc.,1977
5. Topological groups;Comfort,1984