Schmidt, Heinrich, author
New York, Mary S. Rosenberg
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Apel, Max, 1869-1945, author
Berlin : Walter de Gruyter, 1958
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Metzke, E., author
Heidelberg Kerle 1949
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Ziegenfuss, W., author
Berlin de Gruyter 1949
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Julia, Didier, author
Paris, Librairie Larousse
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