by the United States government

“ In the case, however, of copies of works specified in subsections (f) to (k) , inclusive, of section 5 of this title, the notice may consist of the letter C enclosed within a circle, thus ©, accompanied by the initials, monogram, mark, or symbol of the copyright proprietor: Provided, That on some accessible portion of such copies or of the margin, back, permanent base, or pedestal, or of the substance on which such copies shall be mounted, his name shall appear. ”

“ Provided, That if the producer of the sound recording is named on the labels or containers of the reproduction, and if no other name appears in conjunction with the notice, his name shall be considered a part of the notice. ”