@article{imai:kim:19,
  title = {When Should We Use Linear Fixed Effects Regression Models for Causal Inference with Longitudinal Data?},
  author = {Imai, Kosuke and Kim, In Song},
  journal = {American Journal of Political Science},
  year={2019},
  Volume = {63},
  Number = {2},
  Pages = {467--490}
}