or "mutually reverting edit pairs". "Can History be Open Source? Ahrens, Frank (July 9, 2006). Glass had begun using the Farfisa portable organ out of convenience, 105 and he has used it in concert. 75 Glass performing Book of Longing in Milan, September 2008 Other works for the theater were a score for Euripides ' The Bacchae (2009, directed by JoAnne Akalaitis and Kepler (2009 yet another operatic biography of a scientist or explorer. 4041, isbn Richard Serra, Writings Interviews, Chicago: The University of Chicago Press, 1994,. 5 "Choral" (1999) and Symphony. Since Wikipedia is based on the Web and therefore worldwide, contributors to the same language edition may use different dialects or may come from different countries (as is the case for the English edition ). 156 Concerns have been raised by PC World in 2009 regarding the lack of accountability that results from users' anonymity, 157 the insertion of false information, 158 vandalism, and similar problems. "Musical Events: Number Nine".