The 'Basin Facts' table at the beginning of each chapter lists alternative names, which may also be based on lithology and/or age. Extensive aquifer systems that are divided into different sections or basins are generally designated through geographical names for the purpose of this Inventory. For instance, the Umm er Radhuma-Dammam Aquifer System (South) is situated in the Rub' al Khali Desert, which is an integrated part of Saudi Arabia and extends to Oman, UAE, and Yemen, however, reference to Rub' al Khali is meant to specify the geographical area where this section of the aquifer system is situated, but does not serve as an alternative name for the aquifer system itself.