To increase the accuracy of your searches in the online library catalog, include the opus or thematic number of the work if it has one. To locate this number, search in the WORKS list under the composer's name in either Oxford Music Online or the appropriate print volume of the New Grove Dictionary of Music and Musicians in the Reference Room.
The best way to search for scores or recordings is by KEYWORD using the most distinctive words in the author's name and work title.
You can also specify a particular performer.
Use the options on the left side of the results page to refine your search by format or other parameter(s): Music (Printed Music, Music Recordings), Audio, Subject (sonatas (trumpet and piano), concertos (trumpet)), etc.
If UNC-CH doesn't own the piece of music you want, search for it in WorldCat Make a note of the OCLC Accession number of the item you want and include it in your Interlibrary Loan request.