Search the call number MT 446 to find orchestral excerpts for trumpet/cornet. Below are some titles in the library.
The Little Fine Arts Library has several volumes of The Orchestra Musician's CD-ROM Library.
Click on the link to execute an InfoKat Title Browse search for Orchestra Musician's CD-ROM Library to get a complete listing.
You can check these CD-ROMs out to print out the parts you want.
The complete trumpet parts to works by the following composers, among others, are available: