@article {18, title = {Community Size and Network Closure}, journal = {American Economic Review Papers and Proceedings}, volume = {97}, number = {2}, year = {2007}, pages = {80-85}, url = {http://www.jstor.org/stable/30034425}, author = {Hunt Allcott and Dean Karlan and Markus Mobius and Tanya Rosenblat and Adam Szeidl} }