Ghosh, A. “Comparison of Safety and Efficacy of Dextromethorphan and Levocloperastine in Treatment of Dry Cough: A Randomized Open Label Phase IV Clinical Trial”. International Journal of Basic & Clinical Pharmacology, vol. 8, no. 10, Sept. 2019, pp. 2284-7, doi:10.18203/2319-2003.ijbcp20194272.