VARIETIES
The Cherrypickers' Guide to Rare Die Varieties: Fifth Edition - Volume 1, by Bill Fivaz and J.T. Stanton (2008)
The Cherrypickers' Guide to Rare Die Varieties: Fifth Edition - Volume 2, by Bill Fivaz and J.T. Stanton (2011)
Two Dates Are Better Than One - A Collector's Guide to Misplaced Dates, by Kevin Flynn (1997)
Over Mintmarks and Hot Repunched Mintmarks, by Kevin Flynn and John Wexler (2003)
Off-Center and Multi-Denominational Clashed Die, by Kevin Flynn (2013)
Strike It Rich With Pocket Change, by Ken Potter (2013)
The NCADD 10th Anniversary E-Book, by the NCADD Club (CD-ROM) (2008)
Die Variety News (DVN) Magazine, by Billy G. Crawford (CD-ROM) (2011)
The CUD Book, by Sam Thurman and Arnold Margolis (1997)
The Modern Minting Process / U.S. Minting Errors and Varieties, by James Wiles PhD. from the ANA (1997)
The RPM Book, by John Wexler and Tom Miller (1983)
Major Variety and Oddity Guide of United States Coins, by F. G. Spadone (1962)