"HECKMAN MODEL FOR IDENTIFYING THE PROBABILITY OF ADOPTION OF IMPROVED VARIETIES OF SORGHUM, MILLET, GROUNDNUT AND SESAME IN NORTH KORDOFAN STATE, SUDAN" (2025) University of Kordofan Journal of Natural Resources & Enviromental Studies, 5(01), ص 26–43. موجود في: https://journals.kordofan.edu.sd/jr/index.php/ukjnres/article/view/12 (تاريخ الوصول: 1 يناير 2026).