1. Additive set functions in abstract spaces;Alexandroff;Mat. Sbornik,1940
2. An epi-reflector for universal theories;Bacsich;Canad. Math. Bull.,1973
3. Injectivity and essential extensions in equational classes of algebras;Banaschewski,1970
4. Rings of Continuous Functions;Gillman,1960
5. Special morphisms for zero-set spaces;Gilmour;Bull. Austral. Math. Soc.,1975