References for William 1st Earl de Montague * of Salisbury
Sir B. Burke: A Genealogical History of the Dormant, abeyant, forfeited and extinct peerages of the British Empire. London, 1866
F.M.Powicke, E.B.Fryde: Handbook of British Chronology. London, 1961
D.Schwennicke: Europäische Stammtafeln, Vol. XI, Tafel 154. Marburg, 1986