Despite some ambivalence from artists, the term received widespread use by music critics and writers who wrote about artists and albums associated with the musical style. African American studies professor Mark Anthony Neal has described neo soul as "everything from avant-garde R&B to organic soul ... a product of trying to develop something outside of the norm in R&B". According to music writers, the genre's works are mostly album-oriented and distinguished by its musicianship and production, incorporating "organic" elements of classic soul music with the use of live instrumentation, in contrast to the more single-oriented, hip hop-based, and producer-driven sampling approach of contemporary R&B. Neo soul also incorporates elements of electronic music, jazz fusion, funk, rap, gospel, rock, reggae, and African music. In her book "Musical Rhythm in the Age of Digital Reproduction", music author Anne Danielsen wrote that neo soul toward the end of the 1990s exhibited a musical development that was part of "a remarkable increase in musicians' experimentation with and manipulation of grooves at the microrhythmic level – that is, the level in played music that is usually understood in terms of phrasing and timing."