1. The garbage collector and cord package can be retrieved from parcftp.xerox.com/pub/gc/gc.tar.Z.
2. A brief description can be found in parcftp.xerox.com/pub/gc/gc.html.
3. Crisis and aftermath
4. The Art of Computer Programming, Vol. 3, Searching and Sorting, Addision-Wesley, 1973.
5. and , ‘Biased 2–3 trees’, Proceedings of the 21st Annual Symposium on Foundations of Computer Science, IEEE, 1980, pp. 248–254.