Pant, P., Yadav, B., Khan, G., Koju, R., Gurung, R., Pokharel, B., Bedi, T., & Adkhari, R. (2011). Role of tiotropium in chronic obstructive pulmonary disease exacerbation. Journal of Institute of Medicine Nepal, 32(2), 5–10. Retrieved from https://www.nepjol.info/index.php/JIOM/article/view/4937