@InProceedings{Lenzen2010Tight,
	 author =	{Christoph Lenzen and Thomas Locher and Roger Wattenhofer},
	 title =	{{Tight Bounds for Clock Synchronization}},
	 booktitle =	{{Journal of the ACM, Volume 57, Number 2, New York, NY, USA}},
	 month =	{January},
	 year =		{2010}
}