I hope you will find these links helpful.
Lithuania Radio Museum, lots of European Radios
JEWEL’S OLD TIME RADIO’S, An excellent collections of 1920's radios.
Marconi History of Marconi and the Radio Telegraph System.
Midwest Radio Museum. A museum dedicated to the Midwest brand of radios.
Museum of Radio and Technology Links. Lots of good stuff here.
Nostalgia Air Loaded with free schematics and tuning procedures from Rider's Perpetual Troubleshooter Manuals.
Radio Museum membership required to access all info.
Radiola Guy , he has a lot more than Radiola radios on display.
Radiola Guy Links Page lots of interesting links.
RTP (Radio-Television-Portugal) Virtual Museum A fascinating interactive website (not recommended for dial-up)
SWL radio collection This website is in German. Google Chrome has a built-in translator.The Collectors Weekly. A great resource for current radio pricing!