Michele Flammini Alfredo Navarra Stéphane Pérennes The "Real" Approximation Factor of the MST Heuristic for the Minimum Energy Broadcasting. 22-31 2005 conf/wea/2005 WEA http://dx.doi.org/10.1007/11427186_4 db/conf/wea/wea2005.html#FlamminiNP05