فهرس المقالات depobelts حرية الوصول المقاله صفحة الملخص نص كامل 1 - Biomarker application in the recognition of the geochemical characteristics of crude oils from the five depobelts of the Niger Delta basin, Nigeria Timothy Anyanwu Bassey Ekpo Boniface Oriji 10.30495/ijes.2022.1943029.1664