^Mark C. Carnes American National Biography: Supplement 2 0195222024 2005 p.601 "Following the well-regarded 1958 album Singin' the Blues, Witherspoon was recruited as a last-minute addition to the October 1959 Monterey Jazz Festival, where he made a late-night appearance with a band that included Coleman Hawkins, .."
^Chip Deffaa Blue Rhythms: Six Lives in Rhythm and Blues 1996- 0252022033 p.229 "... Singin' the Blues, which was a good album, for Rip Records in 1956, but the company folded soon afterward. In 1958 another small company, World Pacific Records, resurrected the album and re-released it on their label. Singin' the Blues helped spur interest in him in some quarters of the jazz community, and the organizers of the 1959 Monterey Jazz Festival decided they wanted to include Witherspoon in the festival.