@misc{W2029761439,
  author = {Thomas A. Louis},
  title = {Finding the Observed Information Matrix When Using the EM Algorithm},
  year = {1982},
  howpublished = {Journal of the Royal Statistical Society Series B (Statistical Methodology)},
  doi = {https://doi.org/10.1111/j.2517-6161.1982.tb01203.x}
}