Barnard, Chris, author
Pearson Prentice Hall, 2007
Buku Teks
Barnard, C. J.
Harlow Longman Scientific & Technical , 1993
Buku Teks
Bradburn, Norman, author
Jossey-Bass, 2004
Buku Teks
Kador, John, author
McGraw-Hill, 2002
Buku Teks
Whitehead, Malcolm, author
Churchill Livingstone , 1992
Buku Teks