1. Acyclic Models and Resolvent Functors;Appelgate,1963
2. Coequalizers and free triples;Barr;Mathematische Zeitschrifte,1970
3. Distributive laws;Beck,1969
4. The Algebra of Programming;Bird,1996
5. Algebra in the Stone-Cech Compactification: Theory and Applications;Hindman,1998