Argenti, John, author
Allen & Unwin, 1972
Buku Teks
McFarland, Dalton E., author
Collier Macmillan, 1974
Buku Teks
Rice, A K
Tavistock Publications, 1963
Buku Teks
Haire, Mason, author
McGraw-Hill, 1964
Buku Teks
Haire, Mason, author
McGraw-Hill, 1956
Buku Teks