Keen, Maurice H.: The Laws of War in the Later Middle Ages. London 1965, p. 130 n2;
Nicholson, Ranald: The Siege of Berwick, 1333, in: Scottish Historical Review 40 (1961), p. 19-42;
Nicholson, Ranald: Edward III and the Scots: The Formative Years of a Military Career, 1327-1335. Oxford 1965, pp. 123-29;
DeVries, Kelly R.: Infantry warfare in the early fourteenth century. Discipline, tactics and technology (Warfare in history 2). Woodbridge 1996, p. 114 and 121;
Prestwich, Michael C.: Armies and Warfare in the Middle Ages. The English experience. New Haven, Conn., p. 239;
Bradbury, Jim: Medieval Siege. Woodbridge 1992, p. 146 and 332.