Sheldon H. Laskin (Baltimore) has published Only A Name? Trademark Royalties, Nexus, and Taxing That Which Enriches, 22 Akron Tax J. 1 (2007).  Here is the Conclusion:

The Supreme Court got it right in promulgating the business situs rule for taxing intangibles; a state’s authority to tax intangibles cannot be limited by considerations of the intangible’s non-existent physical location. The business situs rule remains the appropriate nexus standard for taxing income from intangibles, including trademark royalty income. As Quill is limited to use tax collection, the state court decisions that uphold the business situs rule for taxing income from intangibles were correctly decided. Although Congress has the power to impose a physical presence nexus rule on the state taxation of income from intangibles, such a rule would be completely incongruous in the modern economy. Instead, nexus should be determined by the application of uniform, easily verifiable economic thresholds that would apply irrespective of the form in which the business provides its services or products. Such a rule is the appropriate measure of a state’s authority to tax the income of remote businesses that benefit from the public services provided by their market state governments.