1. Alan Borning and Daniel Ingalls. Multiple Inheritance in Smalltalk-80. In Proceedings of AAAI'82, pages 234–237, Pittsburgh, Pennsylvania, August 1982.
2. Pierre Cointe. “Object-Oriented Programming: The CLOS Perspective” edited by Andreas Pæpcke, chapter CLOS and Smalltalk, pages 215–250. The MIT Press, Cambridge, Massachusetts, 1993.
3. Scott Danforth and Ira R. Forman. Reflections on Metaclass Programming in SOM. In Proceedings of OOPSLA '94, Portland, Oregon, October 1994.
4. Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides. Design Patterns. Addison-Wesley, Reading, Massachusetts, 1994.
5. Adele Goldberg and Dave Robson. Smalltalk-80: The Language and its Implementation. Addison-Wesley, Reading, Massachusetts, 1983.