Colocating the members of the team, Developers and Customers (including Testers), does wonders for increasing the communication on a project.  And the trust.

 * [[http://www.npd-solutions.com/collocation.html|Enabling Product Development Teams with Collocation]] by Kenneth A. Crow
  "A study in 1977, researching the effect of distance on technical communication, found that the probability of communication rapidly decreases within the first ten meters. Beyond this point, the increase of distance does not seem to have a big impact on communication."
 * [[http://www.possibility.com/Cpp/SoftDevOfficeLayout.html|The Ultimate Software Development Office Layout]] by Todd Hoff
 * [[http://www.agileadvice.com/archives/2005/08/optimizing_a_te.html|Optimizing a Team Room]] by Mishkin Berteig
 * [[http://www.sciam.com/article.cfm?chanID=sa017&articleID=D9058A4E-E7F2-99DF-36023504D1E43BD6&ref=rss|The Science of Team Success]] by Steve W. J. Kozlowski and Daniel R. Ilgen (From the June 2007 issue of Scientific American Mind)
  "Organizational behavior expert Kyle Lewis of the !McCombs School of Business at the University of Texas at Austin found that the development of a team's ability to access distributed knowledge required face-to-face interaction. In groups that communicated exclusively by phone or e-mail, this skill did not emerge."
 * [[http://conway.isri.cmu.edu/~jdh/collaboratory/research_papers/ICIS2002_Proceedings.pdf|Shared Mental Models, Familiarity, and Coordination: A Multi-Method Study of Distributed Software Teams]] by J. Alberto Espinosa et al.
 * [[http://hdl.handle.net/1721.1/1866|A field experiment to improve communications in a product engineering department : the non-territorial office]] by Thomas J. Allen and Peter G. Gerstberger.
 * [[http://possibility.com/Misc/p339-teasley.pdf|How Does Radical Collocation Help a Team Succeed?]] by Stephanie Teasley et al.
  "Companies are experimenting with putting teams into warrooms, hoping for some productivity enhancement. We conducted a field study of six such teams, tracking their activity, attitudes, use of technology and productivity. Teams in these warrooms showed a doubling of productivity. Why? Among other things, teams had easy access to each other for both coordination of their work and for learning, and the work artifacts they posted on the walls remained visible to all."