For Ravens' John Urschel, Playing in the N.F.L. No Longer Adds Up - The New York Times
Former NFL Player Tackles Football And Math
Relatively cheap for John Urschel to retire from the Ravens - NBC Sports
Ravens guard John Urschel drives an impossibly small car : r/nfl
NFL's John Urschel has a brain made for math. And he's willing to risk it on the field. - The Washington Post
John Urschel quit the NFL for a career in math. It wasn't just about the concussions. - The Washington Post
NFL: John Urschel retires from Baltimore Ravens
It all adds up: Lineman John Urschel loves his post-NFL life - /
Why NFL lineman John Urschel benched football for math - CBS News