Richard A. Kelsey's homepage
Scheme 48 has its own web page.
Scheme 48 is an implementation of Scheme based on a byte-code interpreter
It is designed to be used as a testbed for experiments in
implementation techniques and as an expository tool.
Jonathan Rees also has a page describing
Scheme 48 .
I edited R5RS. You can download it as
A page of errata for R5RS is available as
one of the authors of
Scheme 48 manual pages
are now available on-line.
Envision is a extension to Scheme for implementing computer vision algorithms.
Rice University has a large
web site on Scheme.