(perhaps) Boethius, Hector [a.k.a. Boece]. The History and Chronicles of Scotland. Trans. J. Bellenden (c.1540).

(perhaps) Buchanan, George. Rerum Scoticarum Historia (1582).

(perhaps) Camden, William. Remains of a Greater Work Concerning Britain, the Inhabitants Thereof (pr. 1605).

Holinshed, Raphael. The Chronicles of England, Scotland and Ireland (1577). 1587 edtn.

REFERENCE : A.R. Braunmuller, ed. Macbeth. Cambridge: Cambridge University Press, 1997. 13-15.