* The Virtual Valve Museum* The cathode ray tube site* O'Neill's Electronic museum – vacuum tube museum* Vacuum tubes for beginners – Japanese Version* NJ7P Tube Database – Data manual for tubes used in North America.
* The Virtual Valve Museum* The cathode ray tube site* O'Neill's Electronic museum – vacuum tube museum* Vacuum tubes for beginners – Japanese Version* NJ7P Tube Database – Data manual for tubes used in North America.