Srinivasan, N., J. Chandramathi, A. S. Prabhu, and S. Ponthenkandath. “Vitamin D Deficiency and Morbidity Among Preterm Infants in a Developing Country”. International Journal of Contemporary Pediatrics, vol. 4, no. 2, Feb. 2017, pp. 499-02, doi:10.18203/2349-3291.ijcp20170697.