BHASKAR, R. .; SINGH, S. .; SINGH, P. .; SINGH, S. K. .; GAUR, P. S. .; PANDEY, S. . Measurement of Procalcitonin in acute exacerbation of COPD and its correlation to Spirometric Indices. International Journal of Research and Development in Pharmacy & Life Sciences, v. 6, n. 6, p. 2833 - 2839, 15 Nov. 2017.