The rollicking country swing of the Sweetback Sisters is as infectious as it is heartbreaking. Their charismatic charm harkens back to the golden era of both the silver screen cowgirl and the ersatz cowboy stars of local UHF TV kiddie shows. That whimsical exterior is wrapped around a core of deeply felt love for traditional country music styles and a palpable joy in playing and singing together. Like their pseudo-sister role models, the Davis Sisters, the Sweetback Sisters sing country songs...