Cliff, Norman, author
Lawrence Erlbaum Associates, 2003
Buku Teks
Sweets & Zeitlinger, 1989
Buku Teks
Hyde, Harford Montgomery, author
Colorado Alan Swallow , 1948
Buku Teks
Talon, Henri A.
London Longmans 1956
Buku Teks
Yates, Frances A.
Cambridge Cambridge University Press 1934
Buku Teks