Naumkin, Vitaly, and Leonid Kogan. “Dual Principles and Binary Oppositions in Soqotri Social and Oral Traditions”. Proceedings of the Seminar for Arabian Studies, vol. 45, June 2015, pp. 199-05, https://www.archaeopresspublishing.com/ojs/index.php/PSAS/article/view/1279.