Gates, Bill
The road ahead
Viking Press, 1995
Buku Teks SO
Looking ahead: 20 in their 20s
Artikel Jurnal
Steel, Danielle
Changes
Sphere Books, 1991
Buku Teks SO
Murray, Maggie
Streets ahead: student's book 2
Oxford University Press, 1994
Buku Teks SO
Bear, Mariah
Get your IT degree and get ahead
McGraw-Hill , 2000
Buku Teks SO