1. Department of Internal Medicine, Faculty of Medicine , Universitas Sumatera Utara , Dr Mansyur 5 , Medan , Indonesia
2. Department of Child Health, Faculty of Medicine , Universitas Prima Indonesia , Ayahanda 68A , Medan , Indonesia
3. Department of Biomedical Sciences, Faculty of Medicine , Universitas Airlangga , Jl. Mayjen Prof. Dr. Moestopo No.47 , Surabaya , Indonesia