I just happened upon a great research website. A place to browse through more than 100,000 titles of older popular songs in sheet music format. The site is hosted and maintained by Indiana University, and can be accessed by clicking HERE.
This site doesn’t just show the front covers of the songs and tunes, but includes all pages. The collection can be searched by title, composer & author, and first lines.
The original sheet music, later recorded by Charlie Pool and the North Carolina Ramblers as “Goodybye Sweet Liza Jane”.
A lot of interaction occured between the worlds of pop and folk & bluegrass musicians during the past 100 years. Here’s a great place to explore some of those links from the pop side of the equation.