INTERNET SITES:
1. Transistor radio
2. History - history of radio na tv broadcast.
3. United States early radio history.

PAPER SOURCES:
1. Encyclopedia Bulgaria, 1999 edition
2. Short Bulgarian Encyclopedia
3. Broadcasting Propaganda. Philo C. Wasburn, 1992.
4. The Voice of Amerika. Laurien Alexandre, 1986.

VERBAL SOURCES:
Rich Samuels, radio and tv personality.
Stacey Thorp - radio personality.
Ronn Owens, radio and tv personality in SF Bay area.
As well as our elderly reltives - witnesses of the "boom" of television and some of them of radio!