Thompson, F.G.
Longmans, Green and Co, Ltd., 1968
Buku Teks
Thompson, F.G.
Longman Scientific and Technical, 1992
Buku Teks
McPartland, Joseph F.
McGraw-Hill, 1984
Buku Referensi
Marks, Trevor E.
William Ernest, 1992
Buku Teks
edited by Charles A. Harper
McGraw-Hill, 1972
Buku Referensi