09/06/1950
https://www.presidency.ucsb.edu...
"Now, Therefore, I, Harry S. Truman, President of the United States of America, do declare and proclaim:"
"Provided, that the enjoyment by any work of the rights and benefits conferred by the said title 17 shall be conditioned upon compliance with the requirements and formalities prescribed with respect to..."
"And provided further, that the provision of section 1(e) of the said title 17, so far as they secure copyright controlling parts of instruments serving to reproduce mechanically the musical work, shal..."
"That as of this day the conditions specified in section (b) and 1(e) of title 17 of the United States Code exist and are fulfilled with respect to nationals of the Principality of Monaco, and that nat..."