Me pēnei te tohu i te whārangi:
Simon Nathan and Bruce Hayward, 'Ngā whakaahua, ngā rauemi katoa', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/mi/building-stone/media (accessed 28 May 2022)
He kōrero nā Simon Nathan and Bruce Hayward, i tāngia i te 12 Jun 2006