Mainly American soul,blues,gospel,etcetc. They were pretty big Elvis/Chuck Berry/etc..fans and just absorbed all that music along with the Brit 'skiffle' acts that were popular at that time. That's why in the early days,they inserted a few covers into their repertoire-- like Roll Over Beethoven,for example. Most of their covers I'd never heard of the originals,anyway (before my time). And their versions were always better,anyway. T