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Nagumo, J.; Arimoto, S.; Yoshizawa, S. (1962). "An Active Pulse Transmission Line Simulating Nerve Axon". Proceedings of the IRE. 50 (10). Institute of Electrical and Electronics Engineers (IEEE): 2061–2070. doi:10.1109/jrproc.1962.288235. ISSN0096-8390. S2CID51648050.
Nagumo, J.; Arimoto, S.; Yoshizawa, S. (1962). "An Active Pulse Transmission Line Simulating Nerve Axon". Proceedings of the IRE. 50 (10). Institute of Electrical and Electronics Engineers (IEEE): 2061–2070. doi:10.1109/jrproc.1962.288235. ISSN0096-8390. S2CID51648050.
van der Pol, Balth. (1926). "On "relaxation-oscillations"". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 2 (11). Informa UK Limited: 978–992. doi:10.1080/14786442608564127. ISSN1941-5982.
Nagumo, J.; Arimoto, S.; Yoshizawa, S. (1962). "An Active Pulse Transmission Line Simulating Nerve Axon". Proceedings of the IRE. 50 (10). Institute of Electrical and Electronics Engineers (IEEE): 2061–2070. doi:10.1109/jrproc.1962.288235. ISSN0096-8390. S2CID51648050.
Bender, Carl M. (1999). Advanced mathematical methods for scientists and engineers I : asymptotic methods and perturbation theory. Steven A. Orszag. New York, NY. ISBN978-1-4757-3069-2. OCLC851704808.{{cite book}}: CS1 maint: location missing publisher (link)
Grimshaw, R. (1993). Nonlinear ordinary differential equations. Boca Raton, Fla.: CRC Press. pp. 161–163. ISBN0-8493-8607-1. OCLC28275539.