Govindaraj, S., P. Santhakumaran, and S. Thirumalaikumarasamy. “Evaluation of Persistent Pneumonia and Percutaneous Needle Aspiration of Lung As a Tool in the Etiological Evaluation of Children With Persistent Pneumonia”. International Journal of Contemporary Pediatrics, vol. 4, no. 5, Aug. 2017, pp. 1694-00, doi:10.18203/2349-3291.ijcp20173768.