I first encountered the "Bold Fisherman" that Bogart sings in "The African Queen" in A Treasury of Folk Songs, compiled by John and Sylia Kolb and published as a drugstore paperback.
When I first got actively interested in folk music around 1952-53 (dashed out and bought a $10.00 guitar), the dozen or so folk song junkies I fell in with all had copies of the book, so I armed myself with a copy. Everybody had the 1948 edition. I got a reprint, 1953. Same book, different cover, cost 35 cents instead of the previous 25.
I don't recall that anything in it was copyrighted.