Most of the links on this page are broken so here are the archived versions (thanks Internet Archive!):

The CONS protoype (AI Memo 444):

https://web.archive.org/web/20060211063312/http://home.comca...

The CADR (AI Memo 528):

https://web.archive.org/web/20050411174516/http://home.comca...

The Symbolics lisp machine museum:

https://web.archive.org/web/20000605210626/http://kogs-www.i...

After-the-demise symbolics info:

https://web.archive.org/web/20060101010104/http://www.abstra...

P. Tucker Withington's contemporary thoughts:

https://web.archive.org/web/20040810204319/http://www2.theci...

Lisp family tree:

https://web.archive.org/web/20060202000304/http://community....