21.24—References to 1938 edition of Code.
When reference is made to material codified in the 1938 edition of the Code of Federal Regulations, or a supplement thereto, the following forms may be used, as appropriate:
___ CFR, 1938 Ed., ___.
___ CFR, 1943, Cum. Supp., ___.
___ CFR, 1946 Supp., ___.