Berlin Hodder and Stoughton 1966
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London; Cassell LTD., 1978
Buku Referensi
Wichman, Karl, author
Philadelphia, David McKay Company, 1944
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Mansion, J.E., author
London Harrap 1972-1980
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Wessely, J.E., author
Chicago dsb. Pollett Publ. 1946
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