Francis, Thomas George, author
Longman, 1988
Buku Teks
Francis, Thomas George, author
ELBS, 1992
Buku Teks
Francis, Thomas George, author
Longman, 1971
Buku Teks
Whitson, Gene, author
McGraw-Hill, 1996
Buku Referensi
Shuttleworth, Riley
McGraw-Hill, 1983
Buku Teks