1. Berry, B.J.L. and W.L. Garrison, “A Note on Central Place Theory and the Range of a Good,”Economic Geography, Vol. 34 (1958), pp. 304–311. Ullman, E.L., “A Theory for Location of Cities,”American Journal of Socialogy, Vol. 46 (1941), pp. 853–864. Whittlesey D., “The Regional Concept and the Regional Method,”American Geography: Inventory and Prospect, (P.C. James and C.F. Jones, eds.) Syracuse University, Syracuse, 1954.
2. Hammer, C. and F.C. Iklé, “Intercity Telephone and Airline Traffic Related to Distance and the ‘Propensity to Interact‘,”Sociometry, Vol. 20 (1957), pp. 306–316. Harris, C.D.,Salt Lake City: A Regional Capital, University of Chicago, Chicago, 1940. Ullman, E.L.,Mobile: Industrial Seaport and Trade Center, University of Chicago, Chicago, 1940.
3. For example see: Isard, W. and D.J. Ostroff, “General Interregional Equilibrium,”Journal of Regional Science, Vol. 2 (1960) pp. 67–74.
4. Some general statements of graph theory are: König, D.,Theorie der Endlichen und Unenlichen Graphen. Leipzig, 1936 (reprinted by Chelsea Publishing Co., New York, 1950); Berge, C.,Theorie des Graphes et Ses Applications. Dunod, Paris, 1958; Harary, F., “Unsolved Problems in the Enumeration of Graphs,”Publications of the Mathematical Institute of the Hungarian Academy of Sciences, Vol. 5 series A (1960) pp. 63–95;—, “Some Historical and Intuitive Aspects of Graph Theory,”Siam Review Vol. 2 (April 1960) pp. 123–131. The utility of graph theory for geographic analysis has been demonstrated by Garrison, W.L., “Connectivity of the Interstate Highway System,”Papers and Proceeding of The Regional Science Association, Vol. 6 (1960) pp. 121–137.
5. Here, only finite graphs are considered.