Are half of the Seinfeld characters named after TV execs?

My wife and I often noticed that one of the Smallville producers is named “Joe Davola”–leading us to remember (and exclaim at the sight of his name) “Crazy Joe Davola!”

Then, the other day, I heard a news story about ABC exec Lloyd Braun–the name of another Seinfeld character, who was the bane of George’s existence.

I assume these are not coincidences. How many other Seinfeld characters are named for real-life TV folks?