cularly swing, both in urban-based dance bands and blues-influenced country swing (Jimmie Rodgers, Moon Mullican and other similar singers), were among the first music to present African-American sounds for a predominantly white audience. One particularly noteworthy example of a jazz song with recognizably rock and roll elements is Big Joe Turner with pianist Pete Johnson's 1938 single "Roll 'Em Pete", which is regarded as an important precursor of rock and roll. The 1940s saw the increased use of blaring horns (including saxophones), shouted lyrics and boogie-woogie beats in jazz-based music. During and immediately after World War II, with shortages of fuel and limitations on audiences and available personnel, large jazz bands were less economical and tended to be replaced by smaller combos, using guitars, bass and drums. In the same period, particularly on the West Coast and in the Midwest, the development of jump blues, with its guitar riffs, prominent beats and shouted lyrics, prefigured many later developments. In the documentary film Hail! Hail! Rock 'n' Roll, Keith Richards proposes that Chuck Berry developed his brand of rock and roll by trans