Mid-Week Keeping On Song

You wouldn't know by listening to them that these artists are from Sweden.  First Aid Kit is a sisterly duo -- Johanna and Klara Soderberg -- from Stockholm who have immersed themselves in American folk music, and perfected the genre even down to the soft twang.  Their recent appearance on David Letterman introduced them to a wider U.S. audience, and their latest album, "Stay Gold," is heading for the top of Bilboard's folk music chart.