HECKMAN MODEL FOR IDENTIFYING THE PROBABILITY OF ADOPTION OF IMPROVED VARIETIES OF SORGHUM, MILLET, GROUNDNUT AND SESAME IN NORTH KORDOFAN STATE, SUDAN. UKJNRES [انترنت]. 21 ديسمبر، 2025 [وثق 1 يناير، 2026];5(01):26-43. موجود في: https://journals.kordofan.edu.sd/jr/index.php/ukjnres/article/view/12