Esquinas, A. M. “Procalcitonin Measurements and Non-Invasive Mechanical Ventilation in Acute Exacerbation of COPD: An Appropriate New Tool?”. International Journal of Research in Medical Sciences, vol. 2, no. 1, Jan. 2017, pp. 373-4, https://www.msjonline.org/index.php/ijrms/article/view/2155.