 Complete the following phrase:  For their coverage of Super Bowl III at the end of the 1968 season, NBC used Pat Summerall best known for his work for CBS and subsequently, Fox to provide an NFL prospective on the coverage. This was due in part to the fact that NBC was at the time, the network television provider of the American Football League whereas CBS was the network television provider for the pre-merger National Football League. In return, for CBS Radios coverage of Super Bowls 