QST, Dec 1954, p. 4 "coming soon"
QST, Oct 1955, p. 7. (10 months later...)
CQ. Oct 1956, p. 15.
QST, Jan 1957, p. 7. (general info)
References
Brief technical description. Radio News, Oct 1955, p. 70.
Add a frequency shift keyer. CQ, Apr 1964, p. 34.
