ABSTRACT
The analysis of diffusion through the academic landscape of models of internal patterns of cities, as published in “The Nature of Cities” (Harris and Ullman, 1945) in simplified, generalized, and comparative cartodiagrams of concentric zones, sectors, and multiple nuclei, is based on records of 128 citations of the basic article in periodicals and on 309 reproductions of the models in books. The half-life of periodical citations of the article was reached in 1974, 29 years after publication. The half-life of reproduction of the models in books occurred eight years later in 1982, but the peak year was 1995, with 20 new republications.
