"defensator", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
defensator in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
defensator in Ramminger, Johann (2016 July 16 (last accessed)) Neulateinische Wortliste: Ein Wörterbuch des Lateinischen von Petrarca bis 1700, pre-publication website, 2005-2016