It ain't necessarily so - Gershwin, George 1898-1937; Heyward, DuBose 1885-1940; Heyward, Dorothy 1890-1961; Gershwin, Ira 1896-1983 (Sierra Music Publ., 1935)
As recorded by the Bill Potts Big Band on the CD "The jazz soul of Porgy & Bess". - Instrumentation: 5 saxophones, 5 trumpets, 5 trombones, piano, guitar, bass, drums