W.B.C.C.
- Online site of the Worldwide Bi-metallic Collectors Club, created to pool information about this type of coin. Includes catalogue, an image gallery, and all the club's newsletters.
- http://wbcc-online.com/

Joel Anderson: World coins
- An offering of world coins and paper money and associated catalogs. Interesting list of bi-metallic coins for sale, with some scans.
- http://www.joelscoins.com/

Bi-metallics Coins, Tokens
- Includes articles on the subject, and some images.
- http://www.wbcc.fsnet.co.uk/sub003.htm

Ancient to Early Medieval Bi-metallics
- A quick review of early bi-metallic coinage.
- http://www.coinmall.com/CSNA/anc.htm