editor, Ronald Hamowy
Sage Publications, 2008
Buku Referensi
Sloane, Thomas O., author
Oxford University Press, 2001
Buku Referensi
Americana Corporation, 1980
Buku Referensi
Hiebert, Murray, author
Mc Graw-Hill , 2001
Buku Teks
Feather, Leonard, author
Horizon Press, 1960
Buku Referensi