Artikel Jurnal
Seda, Francisia Saveria Sika Ery, author
2005
Artikel Jurnal
Graham, George A.
University of Alabama Press, 1960
Buku Teks
Doran, Charles F., author
Free Press, 1977
Buku Teks
Merriam, Charles E. (Charles Edward), author
New York University Press, 1936
Buku Teks