Thanks for an excellent site. How about a sub forum here for people to submit link corrections? With over 4000 pages dating back over the years there will be some stale links.
I've been looking at Mike Johnston's Understanding Lens Contrast And the Basics of MTF
Tutorial and it links to Harold M. Merklinger's A Technical View of Bokeh at http://fox.nstn.ca/~hmmerk/ATVB.pdf
- it is no longer there but can be found at Harold's site: http://www.trenholm.org/hmmerk/ATVB.pdf