 Covers were customary in the music industry at the time; it was made particularly easy by the compulsory license provision of United States copyright law (still in effect).One of the first relevant successful covers was Wynonie Harris's transformation of Roy Brown's 1947 original jump blues hit "Good Rocking Tonight" into a more showy rocker and the Louis Prima rocker "Oh Babe" in 1950, as well as Amos Milburn's cover of what may have been the first white rock and roll record, Hardrock Gunter's "Birmingham Bounce" in 1949.The most notable trend, however, was white pop covers of black R&B numbers.