Doren, Charles van
Frederick A. Praeger , 1967
Buku Teks SO
Collingwood, R.G.
Clarendon Press, 1946
Buku Teks SO
Daniel, Glyn
Victoria: Penguin Books Australia, 1962
Buku Teks
Sen, Amartya, 1933-
Belknap Press of Harvard University Press, 2009
Buku Teks SO
Sen, Amartya, 1933-
Mass Belknap Press of Harvard University Press, 2009
Buku Teks SO