Abilay, W. P. (1981). Biological constraints to high yields on some rice farms in Nueva Ecija, Philippines [microform]. Photoduplication Service. University of the Philippines Library.
Chicago-referens (17:e uppl.)Abilay, Wenceslao P. Biological Constraints to High Yields on Some Rice Farms in Nueva Ecija, Philippines [microform]. Quezon City: Photoduplication Service. University of the Philippines Library, 1981.
MLA-referens (9:e uppl.)Abilay, Wenceslao P. Biological Constraints to High Yields on Some Rice Farms in Nueva Ecija, Philippines [microform]. Photoduplication Service. University of the Philippines Library, 1981.
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