To cite earlywarnings in publications use:

Vasilis Dakos et al. Methods for detecting early warnings of critical transitions in time series illustrated using simulated ecological dataPLoS One 7(7):e41010, 2012. See http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0041010

Corresponding BibTeX entry:

  @Article{,
    title = {R Early Warning Signals Toolbox},
    author = {Vasilis Dakos and Leo Lahti},
    journal = {The R Project for Statistical Computing},
    year = {2013},
    note =
      {http://cran.r-project.org/web/packages/earlywarnings/index.html},
    url = {Publication URL here},
  }