ISSN 0377-0273. ↑ "HSM 89: Terra Nova Expedition 1910-12, Upper "Summit Camp" used during survey of Mount Erebus in December 1912". Antarctic Treaty Secretariat. Retrieved 27 August 2017. ↑ "HSM 90: Terra Nova Expedition 1910-12, Lower "Camp E" Site used during survey of Mount Erebus in December 1912".