Operation Bullpen: Be aware of these authenticators and autograph sellers - Sports Collectors Digest

Operation Bullpen Bullpen & More, by Kevin Nelson

Book Operation Bullpen Inside Story Biggest Forgery Scam Nelson

Operation Bullpen Author Pens Online Series for SCD On the Craft

How do you authenticate sports memorabilia?

Book Operation Bullpen Inside Story Biggest Forgery Scam Nelson

Revisiting Operation Bullpen and its impact on the autograph hobby

Keeping it real: Operation Bullpen Update - Sports Collectors Digest

Operation Bullpen: Unraveling the Sports Memorabilia Forgery Ring

Operation Bullpen: The Inside Story of the Biggest

Forgery: The bane of the hobby of sports collectors - Sports

operation bullpen - Sports Collectors Digest

Fake Autographs Turn into Real Help for Baseball Charity