Using some of the basic features from serial methodology, Perle combined them with certain elements associated with tonal music to fashion what has been called his "twelve-tone modal method." His Cello Concerto (1966) and Second Serenade (1968) are notable examples of this style. Perle also wrote works in what he viewed as a Read more freer style, that still incorporated twelve-tone techniques, as in his 1958 String Quintet.