ScotstampsErrors and Varieties
inc Forgers/Forgeries
Affordable Foreign Errors.
by Greenlaw.
Catalogue of Errors on U.S. Postage Stamps.
by Steven R Datz.
Constant Varieties of Australia's 1913 1d Kangaroo.
by W C Bell, P Reid in Paperback.
1913 1d Kangaroo Flaw List.
by I Ash, J Sluman in Paperback.
Philatelic Forgers.
by Varro Tyler in Hardcover.
Errors on Postage Stamps, Postage Stamp Varieties, Stamp Forgeries