Gubby, Helen, author
Boon Juridische Uitgevers, 2007
Buku Teks
National Centre for Languange Development, Ministry of Education and Culture Republic of Indonesia, 1995
Buku Teks
Wooldridge, Dean E., author
McGraw-Hill, 1963
Buku Teks
Beer, Stafford, author
John Wiley & Sons, 1981
Buku Teks
Tongku Lee
Buku Teks