Drake, Henry Burgess, author
Oxford University Press, 1951
Buku Teks
Allen, W. Stannard, author
Longman, 1974
Buku Teks
Barnett, E. de Barry, author
Longmans Green, 1957
Buku Teks
Dougan, Dennis L.
London Sweet & Maxwell, Limited 1951,
Buku Teks
Dougan, Dennis L.
Sweet & Maxwell , 1951
Buku Teks