To cite package 'simecol' in publications use:

Petzoldt, T. and K. Rinke (2007). simecol: An Object-Oriented Framework for Ecological Modeling in R. Journal of Statistical Software, 22(9), 1--31. URL http://www.jstatsoft.org/v22/i09/.

Corresponding BibTeX entry:

  @Article{,
    title = {simecol: An Object-Oriented Framework for Ecological
      Modeling in R},
    author = {Thomas Petzoldt and Karsten Rinke},
    journal = {Journal of Statistical Software},
    volume = {22},
    number = {9},
    pages = {1--31},
    year = {2007},
    coden = {JSSOBK},
    issn = {1548-7660},
    url = {http://www.jstatsoft.org/v22/i09},
    keywords = {ecological modeling, individual-based model,
      object-oriented programming (OOP), code-sharing, R.},
  }