'Ernest Weekley and Anne Scott, Collins English Gem Dictionary (London: Collins, 1954).
Rene Descarates, The Philosophical Writings of Descarates, trans. R.Cottingham, R. Stoothoff and D. Murdoch, I (Cambridge: Cambridge University Press, 1984)343. Descarates, The Philosophical 245.
David Hume, An Enquiry Concerning Human Understanding (1748; Indianpolis: Hackett Publishing, 1977) viii.
Jonathan Edwards, Freedom of Will, ed. P.Ramsey (1754; New Haven: Yale University Press, 1957).