Popper, Karl R., author
Routledge & Kegan Paul, 1972, c. 1969
Buku Teks
Popper, Karl R., author
Routledge, 1961
Buku Teks
Bob Baulch, editor
Edward Elgar, 2011
Buku Teks
United Nations Developmen Programme
United Nations Development, 2000
Buku Referensi
Tocqueville, Alexis De, author
Oxford University Press, 1961
Buku Teks