1. 1He first suggested using a political systems approach in, The Political System (New York: Alfred A. Knopf, 1953 ), pp.97 -98 . His first schematic model may be found in, "An Approach to the Analysis of Political Systems,"World Politics, 1957, 384.
2. A framework for research on foreign policy behavior
3. 3Easton David , A Framework for Political Analysis (Englewood Cliffs: Prentice-Hall, Inc., 1965 ), pp.127 -28 .
4. 4Ibid.p.127 .