Christos Levcopoulos Giri Narasimhan Michiel H. M. Smid Improved Algorithms for Constructing Fault-Tolerant Spanners. 144-156 2002 32 Algorithmica 1 http://link.springer.de/link/service/journals/00453/bibs/2032001/20320144.html db/journals/algorithmica/algorithmica32.html#LevcopoulosNS02