1. On the disturbances of pendulums and balances and the theory of escapements;Airy G.B;Trans. Camb. Phil. Soc,1826
2. Andronov A.A Vitt A.A& Khaikin S.E Theory of oscillators. 1966 Oxford UK New York NY:Pergamon Press Dover Publication.
3. Baillie G.H Clutton C& Ilbert C.A Britten's old clocks and watches and their makers. 7th edn. 1956 New York NY:Bonanza Books.
4. Berge P Pomeau Y& Vidal C Order within chaos. 1984 Paris France:Herman.
5. Bernstein D. 2000 Escapements governors ailerons gyros and amplifiers: feedback control and the history of technology. Michigan State University Report.