@inbook {Vava:concave,
	title = {On approximation algorithms for concave quadratic programming},
	booktitle = {Recent Advances in Global Optimization},
	year = {1992},
	pages = {3{\textendash}18},
	publisher = {Princeton University Press},
	organization = {Princeton University Press},
	address = {Princeton, N.J.},
	author = {Vavasis, S. A.},
	editor = {C. A. Floudas and P. M. Pardalos}
}