Which one of the following is not a primary authority of tax law?

A) Code 1245(b)(3) B) Regulations l.47-3(f)(2) C) May v. U.S., 81-1 USTC )[9286, 47 AFTR2d 81-1124, 644 F.2d 578 (CA-6, 1981) D) Bailey, "Using Voting Preferred Stock to Avoid CFC Status," The International Tax Journal 2 (January 1976) pp. 101-13 E) Revenue Rul. 80-219, 1980-2 C.B. 18