APA-viite (7. p.)

Hart, R. D. An ecological systems conceptual framework for agricultural research and development.

Chicago-viite (17. p.)

Hart, Robert D. An Ecological Systems Conceptual Framework for Agricultural Research and Development. [Date of publication not identified].

MLA-viite (9. p.)

Hart, Robert D. An Ecological Systems Conceptual Framework for Agricultural Research and Development.

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