John Urschel quit the NFL for a career in math. It wasn't just about the concussions. - The Washington Post
Ravens' Urschel balancing football, math as he competes for starting job, Professional
AMS :: John Urschel - Mathematician and Pro Football Player
For ex-Raven John Urschel, NFL retirement felt more like a change in careers
John Urschel: From NFL Player to Mathematician
One of the Baltimore Ravens Just Published an Insanely Complex Study in a Math Journal - Bloomberg
John Urschel quit the NFL for a career in math. It wasn't just about the concussions. - The Washington Post
Ex-Raven John Urschel says retirement about math, not concussions
For Ravens' John Urschel, Playing in the N.F.L. No Longer Adds Up - The New York Times
John Urschel makes the best, smartest decision of his life in retiring from the NFL – New York Daily News