@article{Butts2012,
author = {Butts, C.T. and Acton, R.M. and Hipp, J.R. and Nagle, N.N.},
title= {Geographical Variablity and Network Structure},
year = {2012},
doi = {10.1016/j.socnet.2011.08.003},
journal = {Social Networks},
volume = {34},
number = {1},
pages = {82--100},
}