ref: International Times no. 73 (February 12-25, 1970), p. 16, top of column 2. "Jefferson Airplane, Quicksilver Messenger Service, Grateful Dead and Big Brother and the Holding Company are playing for one week commencing Tuesday 10th March. This is still subject to confirmation. Sam Cutler and the Marquee Martin Agency will be handling the concerts." Thanks to runonguiness for bringing this to us.