Sujeet Rajan, Sundeep Salvi, and Jaideep Gogtay. “Confidence, Ease of Use, Satisfaction and Preference of Spacers in Patients With Asthma and COPD: Results from Three Open-Label, Prospective Studies”. World Journal of Pharmaceutical Sciences, vol. 3, no. 7, July 2015, pp. 1387-96, https://wjpsonline.com/index.php/wjps/article/view/spacers-patients-asthma-copd-prospective-studies.