whether by a single composer or those associated with a particular school, movement, or period—is evident to varying degrees in minimalism, post-minimalism, world-music, and other genres in which tonal traditions have been sustained or have undergone a significant revival in recent decades. Some post-minimalist works employ medieval and other genres associated with early music, such as the "Oi me lasso" and other laude of Gavin Bryars. The historicist movement is closely related to the emergence of musicology and the early music revival. A number of historicist composers have been influenced by their intimate familiarity with the instrumental practices of earlier periods (Hendrik Bouman, Grant Colburn, Michael Talbot, Paulo Galvão, Roman Turovsky-Savchuk). The musical historicism movement has also been stimulated by the formation of such international organizations as the Delian Society and Vox Saeculorum. Art rock influence Some composers have emerged since the 1980s who are influenced by art rock, for example, Rhys Chatham. New Simplicity New Complexity New Complexity is a current within today's European contemporary avant-garde music scene, named in reaction to the New Simplicity. Amongst the candidates suggested for having coined the term are the composer Nigel Osborne, the Belgian musicologist Harry Halbreich, and the British/Australian musicologist Richard Toop, who gave currency to the concept of a movement with his article "Four Facets of the New Complexity". Though often atonal, highly abstract, and dissonant in sound, the "New Complexity" is most readily characterized by the use of techniques which require complex musical notation. This includes extended techniques, microtonality, odd tunings, highly disjunct melodic contour, innovative timbres, complex polyrhythms, unconventional instrumentations, abrupt changes in loudness and intensity, and so on. The diverse group of composers writing in this style includes Richard Barrett, Brian Ferneyhough, Claus-Steffen Mahnkopf, James Dillon, Michael Finnissy, James Erber, and Roger Redgate. Developments by medium Opera Notable composers of operas since 1975 include: Michel van der Aa Mark Adamo John Adams Thomas Adès Miguel del Águila Bruce Adolphe Robert Ashley Lera Auerbach Gerald Barry George Benjamin Tim Benjamin Luciano Berio Michael Berkeley Oscar Bianchi Harrison Birtwistle Antonio Braga Rudolf Brucci John Cage Roberto Carnevale Elliott Carter Daniel Catán Tom Cipullo Azio Corghi Michael Daugherty Peter Maxwell Davies Julius Eastman John Eaton Oscar Edelstein Marios Joannou Elia Péter Eötvös Mohammed Fairouz Brian Ferneyhough Lorenzo Ferrero Juan Carlos Figueiras Luca Francesconi Philip Glass Elliot Goldenthal Ricky Ian Gordon Daron Hagen Hans Werner Henze Bern Herbolsheimer York Höller Giselher