Bevilaqua, Fabio; Lidia Falomo; Lucio Fregonese; Enrico Gianetto; Franco Giudise; Paolo Mascheretti (2005). «The pendulum: From constrained fall to the concept of potential». The Pendulum: Scientific, Historical, Philosophical, and Educational Perspectives. Springer. pp. 195–200. ISBN1-4020-3525-X. Consultado em 26 de fevereiro de 2008 gives a detailed description of Huygen's methods