“…The earliest systems were proposed by Orlov in 1928 (Došen 1992), and by Moh (1950), Church (1951), and Ackermann (1956) in the 1950s. Semantics were introduced and developed only much later, in the 1970s; see (Routley and Routley 1972), (Routley and Meyer 1972a), (Routley and Meyer 1972b), (Urquhart 1972), , (Fine 1974), , (Anderson and Belnap 1975), (Routley, Plumwood, Meyer, and Brady 1982), (Anderson, Belnap, and Dunn 1992), and (Brady 2003).…”