Ubaid Ullah Sami, Saeed Ur Rehman, Adnan Ghafoor, Zayed Naser, Saleh Ahmad, Hafeez Ud Din 2022. Serum Vitamin D Level in Chronic Obstructive Pulmonary Disease and its Relation with Severity. Pakistan Journal of Medical & Health Sciences. 16, 09 (Nov. 2022), 941. DOI:https://doi.org/10.53350/pjmhs22169941.