Spence, Nicol C.W.
Wilhelm Fink Verlag , 1976
Buku Teks
Jain, Ravindra K.
Strategic Information and Research Development Centre, 2009
Buku Teks
Vendler, Zeno
Cornell University Press, [1967]
Buku Teks
Cambridge University Press, 1996
Majalah, Jurnal, Buletin
edited by John Lyons
Penguin Books, 1973
Buku Teks