Horsburg, E. M. (Ellice Martin); Napier Tercentenary Exhibition (1914). «Automatic Calculating Machines by P. E. Ludgate». Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition. Gerstein – University of Toronto. [S.l.]: London : G. Bell. pp. 124–127
Ludgate, Percy E. (abril de 1909). «On a proposed analytical machine». Scientific Proceedings of the Royal Dublin Society. 12 (9): 77–91 Available on-line at: Fano.co.UKArquivado em 7 agosto 2019 no Wayback Machine
«Percy Ludgate's Analytical Machine». fano.co.uk. From Analytical Engine to Electronic Digital Computer: The Contributions of Ludgate, Torres, and Bush by Brian Randell, 1982, Ludgate: pp. 4–5, Quevedo: pp. 6, 11–13, Bush: pp. 13, 16–17. Consultado em 29 de outubro de 2018
Ludgate, Percy E. (abril de 1909). «On a proposed analytical machine». Scientific Proceedings of the Royal Dublin Society. 12 (9): 77–91 Available on-line at: Fano.co.UKArquivado em 7 agosto 2019 no Wayback Machine