Took a gamble on this President Coolidge signature....your opinions as to authenticity.

There are two other such prints I've found online that are identically signed, in pencil, but to different recipients.   Mine is signed "To Millard L Hart    With Regards  Calvin Coolidge."

The other was sold by Heritage Auctions in 2009.  One is currently on sale via a Las Vegas dealer who says his version was PSA certified when he bought it.

Being new to this (and reading your forums as a new "student"), is there anyone that knows about such presidential autographs.  Coolidge was a power player from 1910s until his death in 1933.  I'd love to know the story behind this series of print that was clearly distributed to people.