To cite iNEXT in publications use:

T. C. Hsieh, K. H. Ma and Anne Chao. 2019 iNEXT: iNterpolation and EXTrapolation for species diversity. R package version 2.0.19 URL: http://chao.stat.nthu.edu.tw/blog/software-download/.

Anne Chao, Nicholas J. Gotelli, T. C. Hsieh, Elizabeth L. Sander, K. H. Ma, Robert K. Colwell, and Aaron M. Ellison 2014. Rarefaction and extrapolation with Hill numbers: a framework for sampling and estimation in species diversity studies. Ecological Monographs 84:45-67.

Corresponding BibTeX entries:

  @Manual{,
    title = {iNEXT: Interpolation and Extrapolation for Species
      Diversity},
    author = {T. C. Hsieh and K. H. Ma and Anne Chao},
    year = {2019},
    note = {R package version 2.0.19},
    url = {http://chao.stat.nthu.edu.tw/blog/software-download/},
  }
  @Article{,
    title = {Rarefaction and extrapolation with Hill numbers: a
      framework for sampling and estimation in species diversity
      studies},
    author = {Anne Chao and Nicholas J. Gotelli and T. C. Hsieh and
      Elizabeth L. Sande and K. H. Ma and Robert K. Colwell and Aaron
      M. Ellison},
    journal = {Ecological Monographs},
    year = {2014},
    volume = {84},
    pages = {45--67},
  }