Betts, Jonathan Regulators in Bud, Robert; Warner, Debra Jean (1998). Instruments of Science: An Historical Encyclopedia. Taylor & Francis. ISBN978-0-8153-1561-2. p.121
Andrewes, W.J.H. Clocks and Watches: The leap to precision in Macey, Samuel (1994). Encyclopedia of Time. Taylor & Francis. ISBN978-0-8153-0615-3. p.126, this cites a letter of 11 December, but he may have meant the 22 September letter mentioned above.
"Deadbeat escapement". Encyclopedia of Clocks and Watches. Old and Sold Antiques Marketplace. Archived from the original on 20 May 2008. Retrieved 8 June 2008.
Graham, George (1724): An Account of Observations Made of the Variation of the Horizontal Needle at London, in the Latter Part of the Year 1722, and Beginning of 1723. Phil. Trans. 33, 96–107, doi:10.1098/rstl.1724.0020
Graham, George (1748): Some Observations, Made during the Last Three Years, of the Quantity of the Variation of the Magnetic Horizontal Needle to the Westward. Phil. Trans. 45, 279–280, doi:10.1098/rstl.1748.0030
"Deadbeat escapement". Encyclopedia of Clocks and Watches. Old and Sold Antiques Marketplace. Archived from the original on 20 May 2008. Retrieved 8 June 2008.
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Horrins, Joahn (1835). "Appendix 6" . Memoirs of a Trait in the Character of George III. of these United Kingdoms. London – via Wikisource.
Beckett, Edmund; Cunynghame, Henry Hardinge (1911). "Clock" . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 06 (11th ed.). Cambridge University Press. pp. 536–553, see page 541, last few lines. Dead escapements...To get rid of this defect the dead escapement......was invented by G. Graham.
