Riley, Jonathan
Routledge, 1998
Buku Teks
Skorupski, John, author
Routledge: Taylor & Francis Group, 2006
Buku Teks
Mill, John Stuart, author
David Campbell Publisher, 1992
Buku Referensi
Angus & Robertson , 1955
Buku Teks
Mill, John Stuart, author
Yayasan Obor Indonesia, 2005
Buku Teks