1. Alker, H. R, Jr. (1969): A typology of ecological fallacies. Dogan, M. and Rokkan, S. eds.: Quantitative ecological analysis in the spatial science. The Maple Press, Pennsylvania, 69-86.
2. Amrhein, C. G. and Flowerdew, R. (1989): The effect of data aggregation on a Poisson regression model of Canadian migration. Goodchild, M. and Gopal, S. eds.: Accuracy of spatial databases. Taylor and Francis, London, 229-238.
3. Amrhein, C. G. and Flowerdew, R. (1992): The effect of data aggregation on a Poisson regression model of Canadian migration. Environ. Plann. A, 24, 1381-1391.
4. Batty, M. and Sikdar, P. K. (1982a): Spatial aggrega-tion in gravity models: 1. an information-theoretic framework. Environ. Plann. A, 14, 377-405.
5. Batty, M. and Sikdar, P. K. (1982b): Spatial aggrega-tion in gravity models: 2. one-dimensional population density models. Environ. Plann. A, 14, 525-553.