Mint Error News Magazine
- Available both as a print magazine and an online PDF magazine with articles, features, and discoveries of major mint errors (striking errors) from the United States and around the world.
- http://minterrornews.com/

Jason's Error Coins
- Images of a collection of error coins. Wheat cents, Mercury dimes and other assorted.
- http://www.error-coins.com/

Error World
- Internet club devoted to error and variety coinage of all kinds.
- http://www.surok.addr.com/

Rotated Die Coin Census
- Census for US coins with major die rotation of 90 degrees to 180 degrees. Includes fake error detection and measurement indices.
- http://www.rotateddies.com/

World Error Coins
- Describes and illustrates dramatically mis-struck foreign coins. Includes information on recognizing various types of error coins as well as articles on how to get started collecting them.
- http://www.worlderrors.com/

Baker Numismatics
- Photographic image library of coins with doubled dies, repunched mintmarks, over mintmarks, and repunched dates.
- http://www.bakercoins.net/learn/images/

Error Coins Magazine
- Monthly magazine devoted to error coin collecting. Available by subscription.
- http://www.etcmmag.com/

Combined Organizations of Numismatic Error Collectors of America
- National numismatic organization devoted to error and variety collectors.
- http://conecaonline.org/

Silver Dollar VAMs
- Detailed information on silver dollars, specifically Morgan and Peace Dollar die varieties known as VAMs.
- http://www.robjoyce.com/vams

Collecting Error Coins
- Just as nearly every family has its black sheep, virtually every coin series has its failures. These are known as errors or mis-struck coins, and have a following all their own.
- http://studium.com/6/errorcoins.html