See Yigal Shiloh, “Underground Water Systems in the Land of Israel in the Iron Age,” in The Architecture of Ancient Israel: From the Prehistoric to the Persian Periods, ed. Aharon Kempinski and Ronny Reich (Jerusalem: Israel Exploration Society, 1992), pp. 275–293; Dan Gill, “The Geology of the City of David and Its Ancient Subterranean Waterworks,” in Excavations at the City of David 1978–1985, Directed by Yigal Shiloh, Qedem 35 (1966), ed. Donald T. Ariel and Alon DeGroot, pp. 1–28; Dan Gill, “How They Met—Geology Solves Long-Standing Mysteries of Hezekiah’s Tunnelers,” BAR 20:04.