Morris, Richard, author
Simon and Schuster, 1983
Buku Referensi
Popper, Karl R., author
Basic Books, 1959
Buku Teks
Sykes, Bryan, author
Hodder & Stoughton Ltd., 2014
Buku Teks
Von Ward, Paul
Delphi Press, 1981
Buku Teks
Nehru, Jawaharlal, 1889-1964, author
The John Day, 1945
Buku Teks