Posted on the AIS World list; I have not reviewed them yet:

A Transaction Cost Perspective of the “Software as a Service” Business Model. By: Susarla, Anjana; Barua, Anitesh; Whinston, Andrew B.. Journal of Management Information Systems, Fall2009, Vol. 26 Issue 2, p205-240

Campbell-Kelly, M. “Historical Reflections The Rise, Fall, and Resurrection of Software as a Service,” Communications of the ACM (52:5) 2009, pp 28-30.

Choudhary, V. “Comparison of Software Quality Under Perpetual Licensing and Software as a Service,” Journal of Management Information Systems (24:2), Fall 2007, pp 141-165.