2 1 20 Ir. Djoewito Atmowidjojo Primary Author Ir. Waspodo Nartoyo Primary Author Team Inalum Primary Author Ir. Pramusanto Primary Author Ir. Elli Herlia Effendi Primary Author Ir. Adil Djamali Primary Author Ir. Rudi Subagdja Primary Author Ir. Soedjoko Primary Author Ir. Komardi Primary Author mixed material Bandung Lembaga Metallurgi Nasional 1981 Sampurno Additional Author mixed material Bandung Antam 1972