Doan NPN, T. Ha P. Using 15N Isotope Technique for Study the Balance of Nitrogen Fertilizer in Young Rubber Tree -Hevea Brasilliencis. IJSBAR. 2015;24(5):325-330. Accessed January 1, 2026. https://gssrr.org/JournalOfBasicAndApplied/article/view/4837