Dampak lama pemberian packed red cell (PRC) terhadap hemosiderosis pada anak talasemia mayor di ruang melati 2 rumah sakit DR. Moewardi Surakarta = Effect of duration of Packed Red Cell (PRC) transfusion for hemosiderosis in children with major thalassemia at Melati 2 ward of Dr. Moewardi Hospital in Surakarta