Howard Crosby Butler: Early Churches in Syria. Fourth to Seventh Centuries. Princeton University Press, Princeton 1929, p.76
Richard Bernheimer, “An Ancient Oriental Source of Christian Sacred Architecture.” American Journal of Archaeology, vol. 43, no. 4, 1939, pp. 647–668. JSTOR, www.jstor.org/stable/498990. Accessed 6 Jan. 2021
