Hart, R. D. An ecological systems conceptual framework for agricultural research and development.
Čikaški stil citiranja (17. izdanje)Hart, Robert D. An Ecological Systems Conceptual Framework for Agricultural Research and Development. [Date of publication not identified].
MLA način citiranja (9. izdanje)Hart, Robert D. An Ecological Systems Conceptual Framework for Agricultural Research and Development.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.