1. AASHTO (1982). “Standard method of test for resilient modulus of subgrade soils.” Designation T 274-82 Am. Assn. of State Hwy. and Transp. Officials Washington D.C. AASHTO guide for design of pavement structures . (1986). Am. Assn. of State Hwy. and Transp. Officials Washington D.C.
2. The Asphalt Institute. (1982). “Research and development of the Asphalt Institute's thickness design manual ninth edition.” Res. Rep. No. 82-2 College Park Md.
3. Repeated load triaxial testing of a silty clay