BETTS, R HTHOMAS, T1951-06-012009-05-311951-06-012009-05-311951-06-01BETTS RH, THOMAS T. The surgery of patent ductus arteriosus. Journal of the Indian Medical Association. 1951 Jun; 20(9): 309-11http://imsear.searo.who.int/handle/123456789/101373engDuctus ArteriosusJournal Article