Warden III introduced the Five Ring System model in his book, The Air Campaign, contending that any complex system could be broken down into five concentric rings.Hence inclusion to or exclusion from system context is dependent on the intention of the modeler.The human elements of organization and functions are emphasized with their relevant abstract systems and representations.

No model of a system will include all features of the real system of concern, and no model of a system must include all entities belonging to a real system of concern.Attention is paid to all languages and to problems associated with the study and teaching of English as a second or foreign language.

"A Taste of Systemics", isss The Primer Project.", Henry George Liddell, Robert Scott, A GreekEnglish Lexicon, on Perseus Digits Library.