Helander, C. (2002). Farming system research: An approach to developing of sustainable farming systems and the role of white clover as a component in nitrogen management.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Helander, Carl-Anders. Farming System Research: An Approach to Developing of Sustainable Farming Systems and the Role of White Clover as a Component in Nitrogen Management. 2002.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)Helander, Carl-Anders. Farming System Research: An Approach to Developing of Sustainable Farming Systems and the Role of White Clover as a Component in Nitrogen Management. 2002.
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