The following publications are possibly variants of this publication:
- The Theory of Classification, Part 7: A Class is a Type FamilyAnthony J. H. Simons. jot, 2(3):13-22, 2003. [doi]
- The Theory of Classification, Part 11: Adding Class Types to Object ImplementationsAnthony J. H. Simons. jot, 3(3):7-19, 2004. [doi]
- The Theory of Classification, Part 12: : Building the Class HierarchyAnthony J. H. Simons. jot, 3(5):13-24, 2004. [doi]
- The Theory of Classification, Part 1: Perspectives on Type CompatibilityAnthony J. H. Simons. jot, 1(1):55-61, 2002. [doi]