Umm el - Quttein

Sources:

1. Howard Crosby Butler: Early Churches in Syria. Fourth to Seventh Centuries. Princeton University Press, Princeton 1929
2. Hoard Crosby Butler eds., The southern Ḥaurân, Division 2, Ancient architecture in Syria: Section A, Southern Syria ; Part 2, Late E.J. Brill Ltd., Leiden 1909; p. 135 f