Forgery: The bane of the hobby of sports collectors - Sports
Book Operation Bullpen Inside Story Biggest Forgery Scam Nelson
How MLB Authenticates Balls Like Aaron Judge's 60th Homer - The New York Times
An Inside Look at How MLB Authenticates Game-Used Gear
Operation Bullpen Author Shares Some of the Tricks of the Trade of Forgers - Sports Collectors Digest
Fake autographs a multi-million dollar problem for collectors
Operation Bullpen: Be aware of these authenticators and autograph
Where should I sell this? : r/Autographs
Mickey Mantle signed baseball.. help - Blowout Cards Forums