To cite eco in publications use:

Imai K, Lu Y, Strauss A (2011). “eco: R Package for Ecological Inference in 2 x 2 Tables.” Journal of Statistical Software, 42(5), 1–23. https://doi.org/10.18637/jss.v042.i05.

Corresponding BibTeX entry:

  @Article{,
    title = {eco: R Package for Ecological Inference in 2 x 2 Tables},
    author = {Kosuke Imai and Ying Lu and Aaron Strauss},
    journal = {Journal of Statistical Software},
    year = {2011},
    volume = {42},
    number = {5},
    pages = {1--23},
    url = {https://doi.org/10.18637/jss.v042.i05},
  }