1. Banerjee P. K. and Butterfield R. (1981). Boundary element methods in engineering science . McGraw-Hill Inc. London U.K.
2. On the Accuracy of the Bernoulli-Euler Theory for Beams of Variable Section
3. Butterfield R. (1979). “New concepts illustrated by old problems.” Chapter 1 in Developments in boundary element methods P. K. Banerjee and R. Butterfield eds. Vol. 1 Elsevier Applied Science London U.K.
4. Hibbeler R. (1990). Structural analysis 2nd Ed. Macmillan Publishing Co. New York N.Y.
5. ICES-STRUDL. (1977). V3MI 1977 version.