@article {28963,
	title = {Least squares smoothing of univariate data to achieve piecewise monotonicity},
	journal = {Institute of Mathematics and its Applications Journal of Numerical Analysis (IMA J. Numer. Analysis)},
	volume = {11},
	year = {1991},
	pages = {441-432},
	author = {I. C. Demetriou and M. J. D. Powell}
}
