Clarke, Alexander Ross (1 January 1867). "X. Abstract of the results of the comparisons of the standards of length of England, France, Belgium, Prussia, Russia, India, Australia, made at the ordnance Survey Office, Southampton". Philosophical Transactions of the Royal Society of London. 157: 161–180. doi:10.1098/rstl.1867.0010. ISSN0261-0523. S2CID109333769.
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Clarke, Alexander Ross (1 January 1867). "X. Abstract of the results of the comparisons of the standards of length of England, France, Belgium, Prussia, Russia, India, Australia, made at the ordnance Survey Office, Southampton". Philosophical Transactions of the Royal Society of London. 157: 161–180. doi:10.1098/rstl.1867.0010. ISSN0261-0523. S2CID109333769.
web.archive.org
Bennet, Matthew; et al. (2002). "Huygens' Clocks"(PDF). Georgia Institute of Technology. Archived from the original(PDF) on 10 April 2008. Retrieved 4 December 2007., p. 3, also published in Proceedings of the Royal Society of London, A458, 563–579
Bond, Peter; Dupont-Bloch, Nicolas (2014). L'exploration du système solaire (in French). Louvain-la-Neuve: De Boeck. pp. 5–6. ISBN9782804184964. OCLC894499177.
Clarke, Alexander Ross (1 January 1867). "X. Abstract of the results of the comparisons of the standards of length of England, France, Belgium, Prussia, Russia, India, Australia, made at the ordnance Survey Office, Southampton". Philosophical Transactions of the Royal Society of London. 157: 161–180. doi:10.1098/rstl.1867.0010. ISSN0261-0523. S2CID109333769.
Paul., Murdin (2009). Full meridian of glory : perilous adventures in the competition to measure the Earth. New York: Copernicus Books/Springer. ISBN9780387755342. OCLC314175913.