Camil Demetrescu Daniele Frigioni Alberto Marchetti-Spaccamela Umberto Nanni Maintaining Shortest Paths in Digraphs with Arbitrary Arc Weights: An Experimental Study. 218-229 2000 conf/wae/2000 Algorithm Engineering http://link.springer.de/link/service/series/0558/bibs/1982/19820218.htm db/conf/wae/wae2000.html#DemetrescuFMN00