Please cite the following when using 'lmtp' in publications. Citation
should include both the R package article and the paper establishing
the statistical methodolgy.

  Williams N, Díaz I (2023). “lmtp: An R package for estimating the
  causal effects of modified treatment policies.” _Observational
  Studies_. <https://muse.jhu.edu/article/883479>.

A BibTeX entry for LaTeX users is

  @Article{,
    journal = {Observational Studies},
    title = {lmtp: An R package for estimating the causal effects of modified treatment policies},
    author = {Nicholas Williams and Iván Díaz},
    year = {2023},
    url = {https://muse.jhu.edu/article/883479},
  }

  Díaz I, Williams N, Hoffman K, Schneck E (2021). “Non-parametric
  causal effects based on longitudinal modified treatment policies.”
  _Journal of the American Statistical Association_.
  doi:10.1080/01621459.2021.1955691
  <https://doi.org/10.1080/01621459.2021.1955691>.

A BibTeX entry for LaTeX users is

  @Article{,
    journal = {Journal of the American Statistical Association},
    title = {Non-parametric causal effects based on longitudinal modified treatment policies},
    author = {Iván Díaz and Nicholas Williams and Katherine Hoffman and Edward Schneck},
    year = {2021},
    doi = {10.1080/01621459.2021.1955691},
  }