Wernick William. An enumeration of logical functions. Bulletin of the American Mathematical Society , vol. 45 (1939), pp. 885–887.

From the hypothesis of this statement one deduces, using elementary logic, the equation v>(B) — 2iw(A<)wAi(B). The desired conclusion then follows from the inversion rule, v>B(A) w(A)v>AB)/v(B). B is said to be independent of A if the conditional probability v>A(B) equals the absolute probability v>(B). B is independent of A if and only if A is independent of B. A and B are mutually independent if and only if w(AB) w(.A)-w(B). This theorem is then generalized, apparently without adequate definition of terms, to n mutually independent statements. If A and B are mutually independent, then uu(fi) v>X(B) — w(B). The proofs are not highly formalized, and show some confusion between language and syntax, especially in the use of the sign "—*." S. TSURTJ and S. MACLANE