Korkeakivi, Anne, author
Little, Brown and Company, 2012
Buku Teks
Nadya Fitri, author
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2015
UI - Skripsi Membership
Johnson, Carol, author
Allen and Unwin, 1989
Buku Teks
Zainah Anwar, author
Yayasan Mohamed Noah; Petaling Jaya, Selangor, Malaysia , 2011
Buku Referensi
Klaveness, Jan O`Donnell, author
Macmillan, 1983
Buku Teks