Search Primo (the USC Libraries' catalog) for printed music at USC. Most scores are located in the Music Library, some are in remote storage at Grand Library.
Enter the composer's name, work title, and/or thematic catalog number as keywords, then limit Material Type to Scores. For example:
For scores not owned by USC, search in WorldCat then request using Interlibrary Loan and Document Delivery (IDD).
Scores can be difficult to find, due to generic titles like "symphony" or "concerto"; to assist your searching, librarians catalog music with preferred (or uniform) titles, which collect all versions of the same piece under one name. For example, the preferred title for Mozart's 13th symphony is: Symphonies, K.112, F major. To learn more about uniform titles, see Indiana University's Preferred Title guide.
The Reference Scores section of the Music Library is where collected works and critical editions of composers are shelved, as well as monuments, sets, and other series. Since many of these collections have multiple volumes, the individual pieces contained within them are often not included in Primo records.