Davis, Mackenzie Leo, 1941-, author
McGraw-Hill, 2008
Buku Teks
Davis, Mackenzie Leo, 1941-, author
McGraw-Hill, 2013
Buku Teks
Husain, S.K.
Oxford & IBH Publishing Co., 1982
Buku Teks
Centre for research of human resources and the nvironment University of Indonesia, 1991
Buku Referensi
edited by John Pickford
Grosvenor Press International, 1987
Buku Teks