"Müller, Liborius (Germ.). Mint-master at Berlin, 1620-1625, and 1628-1642. His initials L.M. or in monogram appear on his issues, namely Thalers, Goldgulden, and Ducats of 1620, 28, 33, 35, 36, etc., of Georg Wilhelm (1620-1640) and Friedrich Wilhelm, 1641, etc." - Forrer, L. "Biographical Dictionary of Medallists", Bd. 4 (London 1909), S. 194
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