\section*{Acknowledgments}  

The Zelig project would not have been possible without considerable
help from many sources.  Our special thanks go to the \hlink{R core
  team}{http://www.r-project.org/contributors.html} for providing an
excellent modular, open-source platform for the entire statistics and
methodological community.

The authors of the following R packages have provided some of the
models available through Zelig: {\tt MASS} by William N. Venables and
Brian D. Ripley; {\tt MCMCpack} by Andrew D. Martin and Kevin M.
Quinn; {\tt survival} by Terry Therneau and Brian D. Ripley; and {\tt
  VGAM} by Thomas Yee.  

The authors of the following R packages have provided some of the
auxiliary statistical procedures and methods available through Zelig:
{\tt boot} by Angelo Canty and Brian Ripley; {\tt coda} by Martyn
Plummer, Nicky Best, Kate Cowles, and Karen Vines; {\tt sandwich} by
Achim Zeileis; and {\tt zoo} by Achim Zeileis and Gabor Grothendieck.

Our appreciation also goes to Ferdinand Alimadhi, Skyler J.\ Cranmer,
Ben Goodrich, Justin Grimmer, Yang Lin, and Ying Lu, who have
contributed either code or documentation; Dan Hopkins, Ian Yohai, and
others who have given valuable feedback from the courses in which they
have used Zelig as a teaching tool.

For research support, we thank the National Institutes of Aging (P01
AG17625-01), the National Science Foundation (SES-0318275,
SES-0550873, IIS-9874747, SES-0112072), the Mexican Ministry of
Health, the U.S.\ Library of Congress (PA\# NDP03-1), and the
Princeton University Committee on Research in the Humanities and
Social Sciences.

As usual, all errors are our responsibility.

