http://nbc.com/americas-got-talentLindsey Stirling ~ America's Got Talent, Top 48 week-4.The fourth group of 12 from the top 48 take to the stage with their performances, hoping to earn high praise from the judges and the votes from the American viewers to insure that they make it to the next round of competition.©NBC Universal, Inc. SYCO TV & FremantleMedia North America, Inc.