Poisot T (2011). “The digitize package: extracting numerical data from scatterplots.” The R Journal, 3(1), 25-26. http://rjournal.github.io/archive/2011-1/RJournal_2011-1.pdf#page=25.

Corresponding BibTeX entry:

  @Article{,
    title = {The digitize package: extracting numerical data from
      scatterplots},
    author = {T. Poisot},
    journal = {The R Journal},
    year = {2011},
    volume = {3},
    number = {1},
    pages = {25-26},
    url =
      {http://rjournal.github.io/archive/2011-1/RJournal_2011-1.pdf#page=25},
  }