(perhaps) Krantzius, Albertus. Chronica Regnorum Aquiloniorum Dania (1546).

(perhaps) Magnus, Johannes. Historia de Omnibus Sveonumque Regibus (1554).

(perhaps) Saxo Grammaticus. Gesta Danorum, a.k.a. Historia Danica (wr. C12).

REFERENCE : G.E. Bentley. The Jacobean and Caroline Stage. 6 vols. Oxford: Oxford University Press, 1941-68.