issued in 1963, when three values were made available. Postal cancellations The postal cancellations, applied to Turkey's stamps to prevent re-use, carried the name, in Turkish—written in Arabic script—and sometimes also in the Latin alphabet, of the localities where posted. These cancellations have received extensive study by philatelists, who have cataloged several thousand used in the Ottoman Empire. The cancellations include "negative seals," typically a circular stamp in which the Arabic lettering appears uninked against a black background. Philatelic forgeries Stamps of Turkey, especially the nineteenth-century issues, have been extensively forged for the philatelic market, including both rare and common issues. As Fernand Serrane, one of the great experts in stamp forgeries, warned, "Forged overprints pullulate; all the more reason why one should avoid involvement". A number of philatelists have published studies of the forgeries of Turkey. See also PTT (Turkey) The Ottoman Empire Postage stamps and postal history of Hatay Postage stamps and postal history of Iraq Postage stamps and postal history of Palestine List of Ottoman post offices in Palestine List of Ottoman postal rates in Palestine Foreign post offices in Turkey Capitulations of the Ottoman Empire Austrian post offices in the Ottoman Empire French post offices in the Ottoman Empire German post offices in the Ottoman Empire Russian post offices in the Ottoman Empire References and sources Notes Sources John H. Coles & Howard E. Walker ([1984]-1995), Postal Cancellations of the Ottoman Empire, Christie’s-Robson Lowe, London four parts, each a separate volume, identifying cancellations used on stamps throughout the empire, up its end in 1923. Part 1, Europe, is undated but was published in 1984. Part 2, The Lost Territories in Africa & Asia, , is undated. Part 3, Turkey-in-Europe,, is undated. Part 4, Turkey-in-Asia,, is dated 1995. An undated Addendum, Corrigendum and Index was issued for Part 1. Adolf Passer (1938), The Stamps of Turkey, Royal Philatelic Society, London. The major study of the stamps up to 1934, with details on postal history, production methods, local issues, proofs, etc. Further reading Mehmet Ismet Başaran, Tughra Stamps. Erkan Esmer, The Ottoman Empire: a Study of Postal Rates, Routes, Delivery Times and Effects of Historical Events. Menachim Max Mayo, Anatolia. Pulko 2007, Ottoman Empire and Republic of Turkey Postage Stamp Catalogue. The standard catalog (in Turkish) The Duloz Issues of Turkey 1865-1887 formed by Max Plantinga, David Feldman, Geneva 2009. Award-winning collection of Duloz stamps. External links Ottoman