David Hatch and Stephen Millward define pop music as "a body of music which is distinguishable from popular, jazz, and folk musics".[4] According to Pete Seeger, pop music is "professional music which draws upon both folk music and fine arts music".[5] Although pop music is often seen as oriented towards the singles charts it is not the sum of all chart music, which has always contained songs from a variety of sources, including classical, jazz, rock, and novelty songs, while pop music as a genre is usually seen as existing and developing separately.[6] Thus "pop music" may be used to describe a distinct genre, aimed at a youth market, often characterized as a softer alternative to rock and roll.[7]