Haynes, Robert J.
George Allen and Unwin, 1980
Buku Teks
Hartman, Edwin M.
Ballinger Publishing Company, 1988
Buku Teks
Pugh, D. S.
Buku Teks
Rice, A K
Tavistock Publications, 1963
Buku Teks
edited by Christoph Dörrenbächer; Mike Geppert
Emerald Publishing, 2017
Buku Teks