Potter, John M.Anderson, Brian D.O.Stephen Morse, A.2025-06-082025-06-080018-9286ORCID:/0000-0002-1493-4774/work/174739919http://www.scopus.com/inward/record.url?scp=0011821154&partnerID=8YFLogxKhttps://hdl.handle.net/1885/733757883Using elementary systems concepts, a new derivation is given of a recent result [1] characterizing those two-channel systems which can he made single-channel controllable with output feedback.2en197910.1109/TAC.1979.11020560011821154