@article{Diggle1991,
author = {Diggle, P.J. and Chetwynd, A.G.},
title= {Second-Order Analysis of Spatial Clustering for Inhomogeneous Populations},
year = {1991},
doi = {10.2307/2532668},
journal = {Biometrics},
volume = {47},
number = {3},
pages = {1155--1163},
}