About Romex, from the source itself:
http://www.generalcable.com/Assets/AboutUs/RomexAnniversary.pdf Key dates are mentioned here:
http://www.generalcable.com/Sections/About_Us/a_GCCdates.html You'll find some photos of old cable and more here:
http://www.tradeslang.com/ Out of print, but should be available at a library or used from Amazon.com:
Old Electrical Wiring Maintenance and Retrofit by David E. Shapiro
Still in print, I'm not sure how much history is covered here:
Your Old Wiring also by David E. Shapiro
Hope that helps.
