He's Baseball's Only Mud Supplier. It's a Job He May Soon Lose. - The New York Times
MLB's new rules for teams technique of putting mud on baseballs - Sports Illustrated
Rawlings spring catalog by Matt - Issuu
Why do they put mud on baseballs before MLB games? - Quora
Baseball Rubbing Mud
MLB leans on longtime mud supplier, not Rawlings, to coat balls - Sports Illustrated
Baseball Rubbing Mud - Baseball Rubbing Mud
Baseball Has a Dirty Little Secret: Lena Blackburne Rubbing Mud
Lena Blackburne rubbing mud a secret of the game
How to rub up a baseball