@InProceedings{Sommer2009gradient,
	author=	{Philipp Sommer and Roger Wattenhofer},
	title=	{{Gradient Clock Synchronization in Wireless Sensor Networks}},
	booktitle=	{{8th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN), San Francisco, USA}},
	month=	{April},
	year=	{2009},
}