Escribano Úbeda-Portugués, José. «Eric Voegelin: Order and History, vol. IV, The Ecumenic Age. Louisiana State University Press, Louisiana, 1974». Foro Interno, vol. 2, vol. 2, 2002, pp. 166-7, https://revistas.ucm.es/index.php/FOIN/article/view/FOIN0202110166A.