Ashraf, Muhammad Nadeem, et al. “Comparison of Efficacy of Nebulized Salbutamol With Salbutamol Ipratropium Combination in Acute Exacerbation of Chronic Obstructive Pulmonary Disease”. Pakistan Armed Forces Medical Journal, vol. 73, no. SUPPL-1, July 2023, pp. S36-39, doi:10.51253/pafmj.v73iSUPPL-1.2430.