1. Discussion of market choices and optimum city size;Artle,1971
2. Applied Optimal Control;Bryson,1969
3. Sufficient conditions for the optimal control of nonlinear systems;Mangasarian;SIAM J. Control,1966
4. Market choices and optimum city size;Mills,1971
5. Land use in a long narrow city;Solow;J. Econ. Theory,1971