You might also check here, at www.pdmusic.org.

You could also go to the LINKS at the top, on the menu bar and click on it. Then scroll down to the Lester Levy site at Johns Hopkins. Do a Search for the song in the collection. If your song comes up, with sheet music, then that means they consider it to be in public domain.

You can also go here, to the U.S. Copyright Office and search their records.

Good luck,

kat