Michael Prawdin, The Mad Queen Of Spain, (1938) p. 83. Online publicatie
G.A. Bergenroth, Introduction. Letters, Despatches, and State Papers to the Negotiations between England and Spain. Suppl. to vols 1 and 2. London: Longmans, Green, Reader and Dyerm (1868). online publicatie
Michael Prawdin, The Mad Queen Of Spain, (1938) p. 83. Online publicatie