There's a lot of material out there. It was just easier to find (and more of it was in print) during the Bicentennial run-up years ago.

For a single, all-purpose source, I'd recommend Irwin Silber's SONGS OF INDEPENDENCE, Stackpole Books 1973. A lot of libraries do (or did) have copies in the Bicentennial years, and many do yet.

A bit harder to find (I'm guessing) but equally well worth the search is Carolyn Rabson's SONGBOOK OF THE AMERICAN REVOLUTION, NEO Press, Peaks Is., ME 1974.

Either or both of those will give you a lot to go on, and enough bibliography to find a lot more. Both have tunes, well edited.

- George