Lapunzina, Alejandro (2005). “Santa Cristina de Lena, Pola de Lena (near Oviedo), Asturias”. Architecture of Spain. Westport: Greenwood Press. tr. 229–232. ISBN0-313-31963-4.
Conant, Kenneth (1992). Carolingian and Romanesque Architecture: 800-1200. New Haven: Yale University Press. tr. 92. ISBN0-300-05298-7.