Here are the references for PPD files:
[TN5003] Adobe Systems Incorporated, "PostScript Printer Description File Format Specification Version 4.3", Technical Note #5003, February 1996, http://partners.adobe.com/public/developer/en/ps/5003.PPD_Spec_v4.3.pdf
[TN5645] Adobe Systems Incorporated, "Update to PPD Specification Version 4.3", Technical Note #5645, April 1997, http://partners.adobe.com/public/developer/en/ps/5645.PPD_Update.pdf
[CUPSPPD] M. Sweet, "CUPS PPD Extensions", http://www.cups.org/spec-ppd.html
________________________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair
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