The London Hospital / UDO, 1972
Buku Teks
London His Majesty's Stationery Office 1935
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Nicholson, Robert, author
Robert Nicholson Pub., 1988
Buku Referensi
Kanter, Jerome, author
Prentice-Hall, 1970
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Perry, William E., author
John Wiley & Sons, 1981
Buku Teks