To cite evtree in publications use

Thomas Grubinger, Achim Zeileis, Karl-Peter Pfeiffer (2011). evtree: Evolutionary Learning of Globally Optimal Classification and Regression Trees in R. Working Paper 2011-20. Working Papers in Economics and Statistics, Research Platform Empirical and Experimental Economics, Universitaet Innsbruck. URL http://EconPapers.RePEc.org/RePEc:inn:wpaper:2011-20

Corresponding BibTeX entry:

  @TechReport{,
    title = {{evtree}: Evolutionary Learning of Globally Optimal
      Classification and Regression Trees in {R}},
    author = {Thomas Grubinger and Achim Zeileis and Karl-Peter
      Pfeiffer},
    institution = {Working Papers in Economics and Statistics, Research
      Platform Empirical and Experimental Economics, Universit\"at
      Innsbruck},
    year = {2011},
    type = {Working Paper},
    number = {2011-20},
    month = {October},
    url = {http://EconPapers.RePEc.org/RePEc:inn:wpaper:2011-20},
  }