@ARTICLE{Luskin_Dont_2011,
  AUTHOR       = {Robert C. Luskin and John G. Bullock},
  TITLE        = {`Don't Know' Means `Don't Know': DK Responses and the Public's Level of Political Knowledge},
  YEAR         = {2011},
  JOURNAL      = {Journal of Politics},
  volume       = {73},
  number       = {2},
  pages        = {547-57},
  month        = {April},
  URL          = {\url{http://johnbullock.org/DK/}},
}