1. 3. P. Costa Antiquities from Zafar (Yemen), AION n.s. 33: 1973 : 185-206.Costa P. Antiquities from Zafar (Yemen), AION n.s. 36:1976: 445-56. Gibson M & Tindel RD. Archaeological and Environmental Surveys of Yemen. National Geographic Society (NGS) Research Reports: 1978: 215-223. Tindel RD. The History and Culture of Zafar. PhD dissertation submitted to the University of Chicago: 1989.
2. 5. TJ. Wilkinson n.d. A preliminary late Quaternary Chronology for the High Plateau of Yemen. Submitted to GeoArchaeology: 1996 .