An earlier concert featuring mostly US artists and performed live only 10 days after the terrorist attack, has also sold slowly. America: A Tribute To Heroes, featuring Bruce Springsteen, Stevie Wonder, Maria Carey and country star Willie Nelson, has so far only sold 129,000 copies. Billboard's director of charts, Geoff Mayfield, says the CDs may have been released too long after the concerts to hold the public's interest.