 
                            
                        
                        
                        
                                        
                                        Ackoff (1973) "Science in the Systems Age: beyond IE, OR and MS." in: Operations Research Vol 21, pp. 664. 
1970s
                                    
            Cited in: Can Alpaslan, Ian Mitroff (2011) Swans, Swine, and Swindlers: Coping with the Growing Threat of Mega-Crises and Mega-Messes. p. 16. 
1970s, The future of operational research is past, 1979
        
                                        
                                        Ackoff (1973) "Science in the Systems Age: beyond IE, OR and MS." in: Operations Research Vol 21, pp. 664. 
1970s
                                    
                                        
                                        Cited in: Haluk Demirkan, James C. Spohrer, Vikas Krishna (2011) The Science of Service Systems. p. 274. 
1970s, Towards a System of Systems Concepts, 1971
                                    
                                        
                                        Cited in Donella Meadows (2008) Thinking in Systems: a Primer. p. 1. 
1970s, The future of operational research is past, 1979
                                    
Source: 1970s, Redesigning the future, 1974, p. 21 as cited in: Frederick M. Zimmerman (2011) From Riches to Rags at a Time of Prosperity, p. 12.
                                        
                                        As cited in: D.C. (1969) "Systems Theory — A Discredited Philosophy". in: Abacus V. p. 4 
1950s, Problems of Life (1952, 1960)
                                    
“A system is more than the sum of its parts; it is an indivisible whole.”
                                        
                                        It loses its essential properties when it is taken apart. The elements of a system may themselves be systems, and every system may be part of a larger system. 
Ackoff (1973) "Science in the Systems Age: beyond IE, OR and MS." in: Operations Research Vol 21, pp. 664. 
1970s
                                    
Source: General System Theory (1968), 2. The Meaning of General Systems Theory, p. 18
                                        
                                        Russell L. Ackoff and Fred Emery (1972) On purposeful systems, cited in: Lloyd Dobyns, Clare Crawford-Mason (1994) Thinking about quality: progress, wisdom, and the Deming philosophy. p. 40. 
1970s
                                    
Russell L. Ackoff and Fred Emery (1972) On purposeful systems, cited in: Lloyd Dobyns, Clare Crawford-Mason (1994) Thinking about quality: progress, wisdom, and the Deming philosophy. p. 40.