Since the 1960s, creative centers of jazz in Europe have developed, such as the creative jazz scene in Amsterdam. Following the work of drummer Han Bennink and pianist Misha Mengelberg, musicians started to explore by improvising collectively until a form (melody, rhythm, a famous song) is found Jazz critic Kevin Whitehead documented the free jazz scene in Amsterdam and some of its main exponents such as the ICP (Instant Composers Pool) orchestra in his book "New Dutch Swing". Since the 1990s Keith Jarrett has defended free jazz from criticism. British writer Stuart Nicholson has argued European contemporary jazz has an identity different from American jazz and follows a different trajectory.