Demetriou IC. Algorithm 863: L2WPMA: A Fortran 77 subroutine for weighted least squares piecewise monotonic data fitting. ACM Transactions on Mathematical Software. 2007;Vol. 33(1):1-19.

Demetriou IC, Georgiadou SA. The Karush-Kuhn-Tucker Test of Convexity of Univariate Observations and Certain Economic Applications. In: Proceedings of the World Congress on Engineering 2007, Imperial College, London, U.K., 2-4 July. Vol. Vo. II. ; 2007. pp. 967-973.