Wang, C., Y. Shi, and J. Ji. “Application of Block Matching Method-Based Echocardiography Combined With Serum NT-PROBNP Level Detection in the Early Prediction of PDA in premature infants”. Pakistan Journal of Medical Sciences, Vol. 37, no. 6-WIT, Aug. 2021, doi:10.12669/pjms.37.6-WIT.4864.