@article {SternVava2,
	title = {Active set methods for problems in column block angular form},
	journal = {Matem{\'a}tica Aplicada e Computacional},
	volume = {12},
	year = {1993},
	pages = {199{\textendash}226},
	author = {J. M. Stern and S. A. Vavasis}
}
