1. Abed, A M. Geology of Jordan: Al Nahda Al Islamiah Library, Amman, Jordan 460p (2003).
2. Abu- Rukah, Y, and Samawi, M. A study of contamination of the Northen Jordan valley agricultural fields by various metal ions using regression analysis. Qatar Sci. J, 20:155 -165(2000).
3. Adriano, C. Trace Elements in the Terrestrial Environment. Springer-Verlag New York Inc. pp 390-420(1986).
4. Aide, Michael T. Cwick, Gary J.Elemental distributions in Eutric Brunisols from the northern glacial Lake Agassiz region of Manitob. Transactions of the Missouri Academy of , Annual (2002).
5. udel.edu. Internet from 09 Feb 2010 12:00Am