Jack White’s Third Man Records has teamed with Sun Records for a series of 7-inch reissues.  Third Man has announced the first three releases in the series, which are due out on May 21 and convey the diversity of Sun Records’ early roster. The singles are: Johnny Cash’s 1956 tune “Get Rhythm” (which is backed by the far more famous “I Walk the Line”), Rufus Thomas’ 1953 R&B number “Bear Cat,” and the Prisonaires’ 1953 doo-wop hit “Just Walking in the Rain.”