The authors would like to thank the following people:

  Whit Armstrong <Whit.Armstrong@tudor.com>
  - information on model.frame and ideas on merge.zoo performance

  Matthieu Cormec <matthieu.cormec@gmail.com>
  - testing

  Sundar Dorai-Raj <sundar.dorai-raj@pdf.com>

  Ajay Shah <ajayshah@mayin.org>

  Jarek Tuszynski <Jaroslaw.W.Tuszynski@saic.com>
  - performance analysis of R algorithms for rolling analyses
