Bainton, Roland H. (1962): . Princeton: D. Van Nostrand Company Inc. Conant, Kenneth J. (1968): . Cowdrey, H. E. J. (1970): . Evans, Joan (1968): . Oxford: Oxford University Press. Lawrence, C. H. (1984): . Mullins, Edwin (2006): . Rosenwein, Barbara H. (1982): .