Dunga, Jacob Amos, Nura Hamidu Alkali, Mohammed Alkali, Yakubu Mamman Adamu, Bukar Bakki, and Ibrahim Musa Kida. 2015. “Chronic Obstructive Pulmonary Disease As Measured by FEV1, FVC and FEV1 FVC Ratio Among Saw Mill Workers in Jos, Northern Nigeria”. The Nigerian Health Journal 15 (1):1. https://tnhjph.com/index.php/tnhj/article/view/182.