Minimum Cost Network Flow and Transportation Instances

GTE
     "Bad" instances of the minimum cost flow problem provided by the
     Center for Discrete Mathematics and Theoretical Computer Science
     (DIMACS)

Netgen Instances
    Instances of the minimum cost flow problem generated by NETGEN, see
    D. Klingman, A. Napier, and J. Stutz, NETGEN - A program for generating
    large scale capacitated assignment, transportation, and minimum cost flow
    networks, Management Science 20 (1974), 814-820, non-standard problems
    contributed by A. Löbel (ZIB).