Complete Peerage, Location: Mid-Continent Library, Independence @ Alianore Plantagenet, d. of John de Warenne
The cited information was published by St. Catherine Press, 29 Great Queen St, Kingsway, W.C., 1959 (Ref: Alianore Plantagenet, d. of John de Warenne) The author/originator was G.E. Cockayne.