Physical and mechanical characteristic study of unfired composite brick made from mixture of clay sand cement water and coconut fiber with length 1 cm in a closed chamber = Kajian karakteristik fisik dan mekanik batu bata komposit tanpa dibakar campuran tanah, pasir, semen, air dan serabut kelapa panjang 1 cm pada kondisi ruangan - Tri Aditha Nugraha, author (2016)