1. Hilsenrath, J.E.: The economy: Service sector enjoys growth, but pace slows. Wall Street Journal, New York, NY A.2 (2003)
2. Maglio, P.P., Srinivasan, S., Kreulen, J.T., Spohrer, J.: Service systems, service scientists, SSME, and innovation. Communications of the ACM (Special Issue: Services Science) 49, 81–85 (2006)
3. Tien, J.M., Berg, D.: A case for service systems engineering. International Journal of Systems Engineering 12, 13–39 (2003)
4. IBM: Annual Report (2006)
5. Spohrer, J., Maglio, P.P., Bailey, J., Gruhl, D.: Steps toward a science of service systems. Computer 40, 71–77 (2007)