D. Laing, “John Earl of Gowrye, and the Alleged Conspiracy at Perth, August 5, 1600: An Historical Inquiry, in two parts: Part First - The King’s Manifesto; or, ’A Discourse of the Unnatural and Vile Conspiracie,’ &c. Edinburgh, 1600”, PSAS, vol. 12, p. 311, Nov. 1877.