John A. Swain (Arizona) hsa published Reforming the State Corporate Income Tax: A Market State Approach to the Sourcing of Service Receipts, 83 Tul. L. Rev. 285 (2008).  Here is the abstract:

The state corporate income tax is about to undergo its most serious re-examination in over 50 years. The National Conference of Commissioners on Uniform State Laws has initiated a review of the Uniform Division of Income for Tax Purposes Act (UDITPA), which either has been adopted by most states or has been used as a model for similar statutes. UDIPTA employs a three-factor formula to apportion the income of multistate businesses. The property and payroll factors reflect the contribution of the production states, while the sales factor is intended to reflect the contribution of the market states. A weakness of UDITPA is its treatment of services. In computing the numerator of the sales factor, UDITPA attributes service receipts to the state in which the services are performed, regardless of where they are consumed. In the past, place of performance may have been a reasonable proxy for market location, but this is no longer the case. Globalization and advances in computer and communications technology now allow many services to be provided remotely. The Article demonstrates that the UDITPA service receipts attribution rule does not effectively implement the policy of reflecting the contribution of the market states. It also shows that a market-based rule both better effectuates that policy and is administratively feasible. The Article proposes guidelines that should govern revision of the service receipts rule. Finally, the Article considers several additional issues, concluding tentatively that the sourcing of receipts from intangibles should follow a similar approach, commenting on the nexus and throwback rule consequences of a market-based rule, and cautioning that institutional reforms may be necessary in order to ensure that uniformity is achieved and maintained under a new UDIPTA.