4 1 20 Sitanggang Additional Author mixed material 9794163775 Jakarta Pustaka Sinar Harapan 1996 WhatsApp_Image_2025-10-16_at_14.29.28.jpeg.jpeg Sitanggang Primary Author mixed material 9794895547 Jakarta Penebar Swadaya 2003 createthumb_%282%29.jpeg.jpeg Tiurma Sitanggang Primary Author mixed material 9797570819 Depok Kawan Pustaka 2005 download_%282%29.jpeg.jpeg Drs. Tua Sitanggang Additional Author mixed material 9795071874 Jakarta Mitra Gama Widya 1996 WhatsApp_Image_2023-05-23_at_12.42.55.jpeg.jpeg