Goulding, Christina
Sage, 2002
Buku Teks
Glaser, Barney G.
Aldine, 1967
Buku Teks
Howard, Keith
MCB University Press, 1990
Buku Referensi
Chorafas, Dimitris N.
Reinhold Publishing Corporation, 1958
Buku Teks
edited by Joseph F. McCloskey, Florence N. Trefethen
John Hopkins Press, 1954
Buku Teks