Peacock, H.L., author
Heinemann Educational Books, 1980
Buku Teks
Richards, Denis, author
Longman, Green, 1952
Buku Teks
Wasson, Ellis, author
Wiley-Blackwell, 2010
Buku Teks
Keir, David Lindsay, author
Adam and Charles Black, 1946
Buku Teks
Keir, David Lindsay, author
Adam and Charles Black, 1961
Buku Teks