Dobb, Maurice, author
International Publishers, 1947
Buku Teks
Sage Publications, Inc, 2005
Majalah, Jurnal, Buletin
Weber, Max, 1864-1920, author
Routledge Classics , 2001
Buku Teks
Sklair, Leslie, author
Oxford University Press, 2002
Buku Teks
Pigou, A.C. (Arthur Cecil), author
Macmillan, 1958
Buku Teks