Casti, J. & Swain, H.
(1975).
Catastrophe theory and urban processes.
In:
Optimization Techniques Modeling and Optimization in the Service of Man Part 1.
Eds. Cea, J.,
pp. 388-406 Germany: Springer Berlin Hiedelberg.
ISBN 978-3-540-38144-010.1007/3-540-07622-0_483.