Won in the Ninth, by Christopher Mathewson—A Project Gutenberg eBook.
The Rise of the Called Strike - Beyond the Box Score
Aaron Judge's player card from the 2013 MLB Draft : r/baseball
Called Strike Mechanic - Little League
Greg Hansen's 100 Best Days in Tucson Sports History
Controversy aside, Jays oppose expanded video replay
They Call 'Em Like They See 'Em - Twinkie Town
Tom Hawthorn's blog: July 2010
They Call 'Em Like They See 'Em - Twinkie Town
(Richard Peterson) The St. Louis Baseball Reader, PDF, St. Louis Cardinals
Arkansas PBS Sports, AR PBS Sports Baseball State Championship - 6A, Season 2022
July 2011 – Dose of Buffa
SABR's Baseball Cards Research Committee – Page 10
Travelerocity
Umpires Need Replay After Losing Track of Balls and Strikes, Still Get Call Wrong