Complex sentence: Created by Ladd's company, Mayfair Productions, "Box 13" premiered in New York City on December 31,1947, On The Radio Today, New York Times, Dec.31,1947 on Mutual's New York flagship, WOR.
Split into simpler sentences: Created by Ladd's company, Mayfair Productions, "Box 13" premiered in 1947. In New York City, it first aired December 31,1947, On The Radio Today, New York Times, Dec.31,1947 on Mutual's New York flagship, WOR.