 Sheet music can be issued as individual pieces or works (for example, a popular song or a Beethoven sonata), in collections (for example works by one or several composers), as pieces performed by a given artist, etc.When the separate instrumental and vocal parts of a musical work are printed together, the resulting sheet music is called a "score".Conventionally, a score consists of musical notation with each instrumental or vocal part in vertical alignment (meaning that concurrent events in the notation for each part are orthographically arranged).