Coba jelasin Lihat pula dari Al-`Ula dong

Abdul Rahman Ansary, Ḥusayn Abu Al-Ḥassān, The civilization of two cities: Al-ʻUlā & Madāʼin Sāliḥ, 2001, ISBN 9960-9301-0-6, ISBN 978-9960-9301-0-7