Jamie V. Trapp, Tomas Kron, editor
Taylor & Francis Group, 2008
Buku Teks
Frankel, Robert
John Wiley & Sons, 1976
Buku Teks
Addison-Wesley Publishing Company, Inc., 1958
Buku Teks
Thomson, John F.
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Buku Teks
World Health Organization Regional Office for Europe, 1989
Buku Teks