Music publisher numbers may include alpha characters. Plate numbers appear on bottom of pages in a music score. The music publisher number may appear anywhere in music scores, e.g. on the cover, spine, title or title verso page. Matrix numbers are inscribed in the inner circle of LP recordings. There may be different numbers or variations of the same number on a single recording.
Discographies typically list record label and matrix numbers.
G Schirmer - Schirmer publisher no.