You might well be wondering what the difference is between Scholarly, Trade, and Popular sources. Think of these differences, not as absolutes, but on a sliding scale:
More formal structure to article--->Less formal
Peer-reviewed articles--->Editorial review by non-experts
Less advertising--->More advertising
More citations of sources--->Fewer (or no) citations
Fewer (or no) photographs--->More Photographs
Greater use of graphs and statistics--->Lesser emphasis on graphs and statistics
Quantitative data--->Qualitative data
Less frequently published--->More Frequently Published
Here are some examples of Scholarly, Trade, and Popular sources in particular fields of study.
Journal of Jazz Studies/DownBeat/JazzTimes
Journal of Hip Hop Studies/VIBE/GuttaWorld
Allmusic.com--as the name implies, this site provides brief biographical sketches of composers and musical performers in many genres, as well as reviews of their recorded work. There is an element of user input in reviews and articles.
IBDB (Internet Broadway Database)--picks up where the American Song : Musical Theater Companion 1900-1984 leaves off, listing not only opening night cast, crew, and production team, but subsequent cast changes, and lists of understudy and swing actors in Broadway productions up to and including the present day.
Intercollegiate Musical Association--The Intercollegiate Music Association (IMA) was founded in 1960 as a vehicle for enriching and enhancing the development of the students of its member institutions. For over forty-five years, IMA has enhanced the overall ethos of music performance and education for some of the most significant historically black colleges and universities located on the east coast.
Spotify--a free streaming service providing recordings in many musical genres. Commercials are present, but can be eliminated by paying a monthly fee.
Kennett Symphony Orchestra--a semi-professional symphony orchestra based in Chester County PA Their current music director is Michael Hall.
Philadelphia Orchestra--one of the world's great professional symphony orchestras. They currently perform at Verizon Hall in the Kimmel Center, and the Academy of Music. Their current music director is Yannick Nezet-Seguin.
Delaware Symphony Orchestra--a professional symphony orchestra based in Wilmington DE. Their current music director is David Amado.
Allentown Band--The nation's oldest community band, based in Allentown. Their current music director is Ronald Demkee.
Eighth Blackbird--A chamber music group originally based in Oberlin OH.
Edward "Duke" Ellington--One of the giants of Jazz, he influenced and elevated the art form. Read more here.
William James "Count" Basie--Like Ellington, a pianist who led his own band for decades and helped shape big band jazz.
Glenn Miller--Trombonist and band leader from Iowa whose popularity reached rock-star proportions during WWII.
Motown--Founded by Berry Gordy in 1959, this offshoot of Capitol Records has been home to many of America's greatest Black entertainers.
Country Music Hall of Fame--Nashville, Tennessee; chartered in 1964, open since 1967.
Hip-Hop Hall of Fame--a proposed museum for midtown Manhattan; offices are currently in Harlem, New York City.