To cite optM in publications use:

Fitak, R. R. (submitted). optM: an R package to optimize the number of migration edges using threshold models. Journal of Heredity

Corresponding BibTeX entry:

  @Article{,
    title = {optM: an R package to optimize the number of migration
      edges using threshold models},
    author = {Robert R. Fitak},
    journal = {Journal of Heredity},
    year = {submitted},
    volume = {na},
    number = {na},
    pages = {na},
    url = {na},
  }