Butterfield, R., & Douglas, R. A. (1981). Flexibility coefficients for the design of piles and pile groups. Construction Industry Research and Information Association.
Chicago Style (17th ed.) CitationButterfield, R., and R. A. Douglas. Flexibility Coefficients for the Design of Piles and Pile Groups. London: Construction Industry Research and Information Association, 1981.
MLA (9th ed.) CitationButterfield, R., and R. A. Douglas. Flexibility Coefficients for the Design of Piles and Pile Groups. Construction Industry Research and Information Association, 1981.
Warning: These citations may not always be 100% accurate.