The authors would like to thank the following people for ideas,
testing and feedback regarding zoo:
  Whit Armstrong <Whit.Armstrong@tudor.com>
  Matthieu Cormec <matthieu.cormec@gmail.com>
  Spencer Graves <spencer.graves@pdf.com>
  Sundar Dorai-Raj <sundar.dorai-raj@pdf.com>
  Dirk Eddelbuettel <edd@debian.org>
  Kurt Hornik <Kurt.Hornik@R-project.org>
  Roger Koenker <roger@ysidro.econ.uiuc.edu>
  Thomas McCallum <termcc@googlemail.com>
  Deepayan Sarkar <deepayan.sarkar@gmail.com>
  Ajay Shah <ajayshah@mayin.org>
  Jarek Tuszynski <Jaroslaw.W.Tuszynski@saic.com>
