Tolong jelaskan mengenai Logo versi dari NBC

NBC corporate archive at the Wisconsin Historical Society - The original NBC office files from 1921-1955 (1.2 million documents, 3100 audio recordings)

Screen captures of NBC logos past and present as well as footage of vintage promos

NBC press releases and photos on NBC Universal Media Village

Rockefeller Center (NBC's '30 Rock' headquarters building) official site