Donaldson, Bruce
Mastering German vocabulary : a practical guide to troublesome words
Routledge, 2004
 Buku Referensi
McKeane, Alasdair
German
Longman, 1994
 Buku Teks SO
Economics: mastering
Prentice-Hall, 2002
 Multimedia
Mastering symphony
[publisher not identified], [date of publication not identified]
 Buku Teks SO
O`Donnell, Gerard
Mastering sociology
Macmillan, 1994
 Buku Teks SO