Chen, S., W. Ye, W. Zheng, Z. Xu, Y. Chen, and L. Jin. “Increased Serum Antimicrobial Peptide LL-37 and HBD-2 Combined With 25-Hydroxyvitamin D3 Deficiency in Infants With Pertussis”. The Journal of Infection in Developing Countries, Vol. 14, no. 10, Oct. 2020, pp. 1164-9, doi:10.3855/jidc.12317.