Michael Paulitsch Wilfried Steiner Fault-Tolerant Clock Synchronization for Embedded Distributed Multi-Cluster Systems. 249-256 2003 conf/ecrts/2003 ECRTS http://csdl.computer.org/comp/proceedings/ecrts/2003/1936/00/19360249abs.htm db/conf/ecrts/ecrts2003.html#PaulitschS03