found: LCCN 59-15055: His Digital computer and control engineering, 1960(hdg.: Ledley, Robert Steven)
found: LC data base, 12-19-93(hdg.: Ledley, Robert Steven; usage: Robert Steven Ledley)
found: Theoretical analysis of force distribution on lower partial dentures with symmetric saddles, 1969:cover (R.S. Ledley, National Biomedical Research Foundation, Silver Spring, Md.)
found: New York times WWW site, July 26, 2012(in obituary published July 25: Robert S. Ledley; b. Robert Steven Ledley, June 28, 1926, Flushing, Queens; d. Tuesday [July 24, 2012], Kensington, Md., aged 86; dentist turned biomedical researcher and computing trailblazer who invented the first CT scanner capable of producing cross-sectional images of any part of the human body)