@techreport{Aldstadt1998,
author = {Aldstadt, J. and Chen, D.M. and Getis, A.},
title= {Point Pattern Analysis (PPA) online software (Version 1.0a): K-Function (second-order analysis) and Local Gi* statistic},
year = {1998},
URL = {http://www.nku.edu/~longa/cgi-bin/cgi-tcl-examples/generic/ppa/ppa.cgi},
publisher = {San Diego State University, Department of Geography},
}