1. G. Ahlbrand: Endlich axiomatisierbare Theorien von T 3 -Räumen, Diplomarbeit, Freiburg (1979).
2. W. Baur: Undecidability of the theory of abelian groups with a subgroup, Proc. AMS 55 (1976), pp. 125–128.
3. N. Bourbaki: Algèbre (Modules sur les anneaux principaux), Paris (1964).
4. N. Bourbaki: Algèbre commutative (Valuations), Paris (1964).
5. Charlotte N. Burger: Some remarks on countabletopological spaces. Seminarreport, FU Berlin (1971).