Mark E. Berg (Feingold & Alpert, New York,) has published Judicial Deference to Tax Regulations: A Reconsideration in Light of National Cable, Swallows Holding, and Other Developments, 61 Tax Law. 481 (2008).  Here is part of the Conclusion:

Although (or perhaps because) much ink has been spilled by courts and commentators regarding the standards to be applied in determining whether a tax regulation is valid, confusion reigns. This Article identifies three categories of congressional delegations of regulation writing authority—purpose delegations, provision delegations, and mixed delegations—all of which have traditionally been treated as delegations authorizing the promulgation of “legislative regulations,” and concludes that the National Muffler standard survived the Supreme Court’s decisions in Chevron, Mead, and National Cable, and remains the applicable standard not only for section 7805(a) regulations but also for tax regulations promulgated pursuant to purpose delegations, provision delegations, and the portion of a mixed delegation other than the enumeration of specific matters to be covered in the regulations.