To cite 'sharx' in publications use with package version number:

Sólymos P, Lele SR (2012). “Global pattern and local variation in species-area relationships.” Global Ecology and Biogeography, 21, 109–120.

Corresponding BibTeX entry:

  @Article{,
    title = {Global pattern and local variation in species-area
      relationships},
    author = {P\'{e}ter S\'{o}lymos and Subhash R Lele},
    journal = {Global Ecology and Biogeography},
    year = {2012},
    volume = {21},
    pages = {109--120},
  }