Laybourn, Ann
Edinburgh HMSD , 1994
Buku Teks
Buzan, Tony, author
Gramedia Pustaka Utama , 2005
Buku Teks
William Damon, editor-in-chief
John Wiley & Sons, 1998
Buku Referensi
William Damon, editor-in-chief
John Wiley & Sons, 1998
Buku Referensi
William Damon, editor-in-chief
John Wiley & Sons, 1998
Buku Referensi