One should certainly start with the above references, but here are a
few of the better web sources:

http://www.ischool.utexas.edu/~hollyr/portfolio/projects/instadiscs/instadiscs.doc
(fairly in-depth, but also a school project so perhaps less authoritative)
see also:
http://www.ischool.utexas.edu/~hollyr/portfolio/projects/instadiscs/patent.html

more for fun than research:
http://www.snapshotsinsound.com/
http://www.lexpages.com/weirdrecords/weirdrecords.html
http://www.phonozoic.net/recordio/

I'd be interested in hearing about what might be incorrect in the
above instances too.

-Franz Kunst