@article {Demetriou-Powell-1991,
	title = {The minimum sum of\&nbsp;squares change to univariate data that gives convexity},
	journal = {IMA J.Numer. Analysis},
	volume = {11},
	year = {1991},
	pages = {433{\textendash}448},
	author = {I. C. Demetriou and M. J. D. Powell}
}
