Vermeer's signature, The Astronomer, 1668.
Musée du Louve, Paris: acquisition number RF 1983 28.
Source: Essential Vermeer.
Antique Jewelry University
The AJU includes listing of jewellery makers' marks.
Art Signature Dictionary
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Benezit Dictionary of Artists
Some entries include signatures.
ICD (International Ceramics Directory)
Links to examples of ceramic marks by country of origin.
Silver Marks, Hallmarks & Maker's Marks
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