@article{King2006,
author = {King, G. and Zeng, L.},
title= {The dangers of extreme counterfactuals},
year = {2006},
doi = {10.1093/pan/mpj004},
URL = {http://gking.harvard.edu/files/abs/counterft-abs.shtml},
journal = {Political Analysis},
volume = {14},
number = {2},
pages = {131--159},
}