Djer, M., and B. Madiyono. “Blood Nickel Level and Its Toxic Effect After Transcatheter Closure of Persistent Duct Arteriosus Using Amplatzer Duct Occluder”. Paediatrica Indonesiana, Vol. 49, no. 1, Mar. 2009, pp. 33-8, doi:10.14238/pi49.1.2009.33-8.