Tiffany, Lawrence P., author
Little, Brown, 1967
Buku Teks
Mudiyati Rahmatunnisa, author
Research and Development Agency Ministry of Home Affairs, 2018
Artikel Jurnal
University of Queensland Press, 1972
Buku Teks
Routledge, 1993
Buku Teks
Williams, Phil, author
Thomson Wadsworth, 2006
Buku Teks