Clarke, A. R.; James, Henry (1867). "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. S2CID109333769.
entreprises.gouv.fr
"Histoire du mètre". Direction Générale des Entreprises (DGE). Retrieved 27 December 2017.
Clarke, A. R.; James, Henry (1867). "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. S2CID109333769.