Frank Lorimer, The Growth of Reason (London: K. Paul, 1929); цит. по: Arthur Koestler, The Act of Creation (London: Penguin, 1964), стр. 616.

Dwight L. Bolinger, ed., Intonation: Selected Readings. (Harmondsworth, U.K.: Penguin, 1972), стр. 314; Alan Cruttenden, Intonation (Cambridge, U.K.: Cambridge University Press, 1986), стр. 169–171.