1. Heuristische Verfahren zur Lösung quadratischer Zuordnungsprobleme;Burkard;Zeitscher. für O.R.,1975
2. Graphs and Hypergraphs;Berge,1973
3. The computer-assisted heuristic approach used to schedule the major league baseball clubs;Cain,1977
4. Graph Theory;Harary,1969
5. Cluster analysis and mathematical programming;Rao;J. Amer. Statist. Assoc.,1971