“…There are many variants of this problem depending on the underlying graph structure (single path (Potters and Sudhölter, 1999), tree (Megiddo, 1978;Bjørndal et al, 2004;Maschler et al, 2010), complete graph (Bird, 1976;Huberman, 1981, 1984), etc. ), on whether the nodes carry cost (or a reward) or not (Granot and Maschler, 1998;van den Nouweland et al, 1993), and on whether there are one or more sources (Rosenthal, 1987;Granot and Granot, 1992;Kuipers, 1997).…”