^Ma, Jinshuang (12 november 2003). ”Rediscovery of the 'first collection' of the 'Living Fossill', Metasequoia glyptostroboides”. Taxon "52": ss. 585–8.
^Copeland, B. Jack, red (2006). Colossus: the Secrets of Bletchley Park's Codebreaking Computers. Oxford University Press. ISBN 978-0-19-284055-4