Surat na di Toru
d Ida ma The Encyclopedia of Religion, Jilid 4, halaman 165; The Encyclopedia Americana, Jilid 8, halaman 246; dohot Symbols Around Us, halaman 205-207.
d Ida ma The Encyclopedia of Religion, Jilid 4, halaman 165; The Encyclopedia Americana, Jilid 8, halaman 246; dohot Symbols Around Us, halaman 205-207.