Hanna, Julia. “Bringing ‘Lean’ Principles to Service Industries”. HBS Working Knowledge. October 22, 2007. (Summary article based on published research of Professor David Upton of Harvard Business School and doctoral student Bradley Staats: Staats, Bradley R., and David M. Upton. “Lean Principles, Learning, and Software Production: Evidence from Indian Software Services.”. Harvard Business School Working Paper. No. 08-001. July 2007. (Revised July 2008, March 2009.)