@book{26676,
	author = {Williamson, David P. and Shmoys, David Bernard.},
	title = {The design of approximation algorithms /},
	publisher = {Cambridge University Press,},
	year = {2011.},
	address = {New York :},
	url = {http://assets.cambridge.org/97805211/95270/cover/9780521195270.jpg}
}