1. "The Pressures Generated in Soil by Compaction Equipment" by A. C. Whiffin A.S.T.M. 1953 Tech. Publ. No. 156 p. 186.
2. 2• "Study of the Relationship Between Energy per Blow and Compaction of Sand" by V. E. Vaughan Report to Franki of Canada Ltd. 1957 unpublished.
3. Static and Dynamic Soil Compaction", by R. K. Bernhard, Proceedings, Highway Res. Bd;Wash.,1952
4. The Importance and Practical Use of Relative Density in Soil Mechanics", by D. M. Burmister, Proceedings;A. S. T. M.,1948
5. "Soil Mechanics in Engineering Practice" by K. Terzaghi and R. B. Peck J. Wiley New York 1948.