Hanrahan, Pat. From Radiometry to the Rendering Equation. SIGGRAPH
Course Notes: An Introduction to Radiosity (1992).
and
Kajiya, Jim "Radiometry and Photometry for Computer Graphics,"
Advanced Topics in Ray Tracing, SIGGRAPH '90 Course Notes, vol. 24,
Aug. 1990.
I have looked on the ACM SIGGRAPH website. They do not have them :-
( Please contact me if you have a copy!
heniser at yahoo dot com
Thanks,
Ryan