Worldcat@SU allows you to limit your results to Musical Scores from the results screen by using the Format checkbox to indicate that you are looking for a Musical score.
The library's printed scores are shelved by call number in the Music Library in SLC 111.
Because musical works can be recorded or published with varied versions of a title (popular title, title in original language or translation, etc.) they can be especially tricky to find. Library catalogers create "uniform titles" for each work to help researchers find the varied iterations of a score or recording.
The Cook Music Library at the Indiana University School of Music has a good website about uniform titles. Follow the link below and use the navigation in the site's left-hand column to learn more.
Song indexes can be of assistance in locating a particular song in published collections. Be sure to start with a Worldcat@SU search for the song title. Some of the older song indexes can be a bit tricky to use at first, so if you have any questions, please ask a librarian!
Here are some selected song indexes to get you started: