Jan Cheyns Chris Develder Didier Colle Erik Van Breusegem Piet Demeester Cost Efficient Upgrading of OPS Nodes. 71-78 2004 conf/opnetec/2004 OpNeTec http://dx.doi.org/10.1007/0-387-23178-1_8 db/conf/opnetec/opnetec2004.html#CheynsDCBD04