Muhammad Younus, Kamal Din, Sohail Anwar, Yasir Nasir. “Effect of Probiotic Oral Suspension on Disease Severity in Chronic Obstructive Pulmonary Disease Patients-A Randomized Control Trial”. Pakistan Journal of Medical & Health Sciences, vol. 16, no. 08, Oct. 2022, p. 757, doi:10.53350/pjmhs22168757.