1. Daniel G. Bobrow, Linda G. DeMichiel, Richard P. Gabriel, Sonya Keene, Gregor Kiczales, and David A. Moon, Common Lisp Object System Specification, X3J13 Document 87–002.
2. Daniel G. Bobrow, Kenneth Kahn, Gregor Kiczales, Larry Masinter, Mark Stefik, and Frank Zdybel, “CommonLoops: Merging Lisp and Object-Oriented Programming,” ACM OOPSLA Conference, 1986.
3. Adelle Goldberg and David Robson, Smalltalk-80: The Language and its Implementation, Addison-Wesley, Reading, Massachusetts, 1983.
4. Guy L. Steele Jr., Common Lisp: The Language, Digital Press, 1984.
5. Reference Guide to Symbolics Common Lisp: Language Concepts, Symbolics Release 7 Document Set, 1986.