Lehmann, Winfred P., author
Holt, Rinehart & Winston, 1973
Buku Teks
Lehmann, Winfred P., author
Holt, Rinehart and Winston, 1962
Buku Teks
Barber, Charles
Cambridge University Press, 1993
Buku Teks
Campbell, Lyle, author
Edinburgh University Press , 2013
Buku Teks
edited by Charles Jones
Longman, 1993
Buku Teks