C. Lee 
Models in Planning [PDF ebook] 
An Introduction to the Use of Quantitative Models in Planning

Models in Planning: An Introduction to the Use of Quantitative Models in Planning focuses on some of the techniques utilized for the construction of urban and regional models, with emphasis on the understanding of model structure rather than on rigorous mathematical analysis. Organized into eight chapters, this book begins by explaining the role of models in the planning process. Subsequent chapters elucidate the principles for the design and use of models, and the mathematical preliminaries involved. The different models, namely, linear, gravity, and Lowry models, are also described including their optimization. This material will be very useful for students and practicing planners with a limited numerate background. It will allow readers to follow up the extensive literature dealing with the more complex operational versions of the discussed models.