I'd strongly recommend anything written by John Bagot Glubb. Unfortunately, he doesn't really have any articles but he's written about twenty books on the Middle East, tribes, war-fighting, etc. He served in Iraq and Jordan from 1920 to 1956 and finished his career as the Commander of the Jordanian Arab Legion. The best books for your mission are probably "The Story of the Arab Legion", "A Soldier With the Arabs", "War in the Desert: An R.A.F. Frontier Campaign," and "Arabian Adventures: Ten Years of Joyful Service." He literally took nomadic Bedouin tribes and trained them into the most effective military force in the Middle East. The books are somewhat difficult to find but any used book website will have probably have them.