I don't know the date of this document. It is not dated, and was probably attached to another letter which I no longer have. However, it refers to the possibility of playing a chess game by computer between July 15th and July 18th, presumably of 1968. That was not possible on our end. I didn't bring my amateur radio rig into the lab and get it operating with Greenblatt's antenna until October 1, 1968.