BARKER JOEL ARTHUR. (1993). PARADIGMS: THE BUSINESS OF DISCOVERING THE FUTURE. HARPER COLLINS PUBLISHERS.
Chicago-viite (17. p.)BARKER JOEL ARTHUR. PARADIGMS: THE BUSINESS OF DISCOVERING THE FUTURE. NEW YPRK: HARPER COLLINS PUBLISHERS, 1993.
MLA-viite (9. p.)BARKER JOEL ARTHUR. PARADIGMS: THE BUSINESS OF DISCOVERING THE FUTURE. HARPER COLLINS PUBLISHERS, 1993.
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