Greta, Stella and Sunniva Bondessen are Baskery, three blue-eyed, blonde-haired sisters from Sweden who have obviously spent a lifetime immersed in the sounds and styles of classic American country and bluegrass music. With a ramped-up approach they sometimes call “killbilly,” “banjo punk” or “mud-country,” and featuring ridiculously tight harmonies, their album Fall Among Thieves could teach a thing or two to so-called porch-punk purveyors of pared-down pap presented right here on American shores. Energy is the backbone of Baskery, but the trio also have considerable chops, recording completely live in one room around one microphone with no overdubs. Just the same way the Stanley Brothers did it. The same way Johnny Cash did it. The same way Elvis (before he got fat) did it. Witness the sibling synchronicity on Tuesday, July 20, at the Mystic Theatre. 21 Petaluma Blvd. N., Petaluma. 8:30pm. $15. 707.765.2121.