Guicciardini, Francesco. The History of Guicciardin. Trans. Geoffrey Fenton (1599). Poss. read both in Italian original and in Eng. trans.

Machiavelli, Niccolò. Discorsi Sopra la Prima Deca di Tito Livio (1531). 3.6.

Petrus de Abano. Heptameron, sev Elementa Magica (pr. c.1565).

Widman, George Rudolf. Der Dritte Theil der Historien von Doct. Johannes Fausto (Hamburg, 1599).

REFERENCE : Jim C. Pogue, ed. 'The Devil's Charter' by Barnabe Barnes: A Critical Edition. New York: Garland, 1980. 6-22.