Leitch, Alexander (1978). A Princeton Companion. Princeton, NJ, USA: Princeton University Press. pp. 135f, 181, 198f, 292, 376. Retrieved 22 August 2015. Alt URL
Leitch, Alexander (1978). A Princeton Companion. Princeton, NJ, USA: Princeton University Press. pp. 135f, 181, 198f, 292, 376. Retrieved 22 August 2015. Alt URL