What is the current state of the law on disclosure of income tax information?

The majority holds, and I agree, that the rule of United States v. Sullivan, 274 U.S. 259, 47 S.Ct. 607, 71 L.Ed. 1037 (1927), requires all citizens to file income tax returns despite the obvious hazards of self-incrimination. The majority makes a proper application of this rule to require disclosure of the sources of a taxpayer's income. ¹ The majority then holds, and I disagree, that the appellant's Fifth Amendment privilege prevents the use of volunteered answers as evidence in this non-tax prosecution.