1.   Allied Electronic Data Handbook
  2.       Heathkit Part No Cross Ref
  3.     Private Brand Radio Names
  4.          RCA Radiotron & Station Directory - 1929
  5.       Sams Photofacts Index by Year
  6.        Zenith R7000 Transistor Cross Ref
  7.      Zenith Replacement Component
  8.      Ballast Tube Handbook