1. Abdelghany Y. 2008. Monotonic and Cyclic Behavior of Helical Screw Piles Under Axial and Lateral Loading. Ph.D. thesis The University of Western Ontario Canada.
2. ASTM International. Standard Test Method for Individual Piles Under Static Axial Tensile Load. Designation D3689-90 (Reapproved 1995). West Conshohocken PA USA.
3. ASTM International. Standard Test Method for Individual Piles Under Static Axial Compressive Load. Designation D 1143-81 (Reapproved 1994). West Conshohocken PA USA.
4. Prakash S. and Sharma H.D. 1990. Pile foundations in engineering practice. John Wiley and Sons New York N.Y.