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2. A. J. Lotka, Elements of Physical Biology (Williams and Wikins, Baltimore, 1924).
3. L. S. Pontryagin, Ordinary Differential Equations (Nauka, Moscow, 1965; Addison-Wesley, Reading, Mass., 2014).
4. V. Volterra, Leçons sur la théorie mathématique de la lutte pour la vie (Marcel Brelot, Paris, 1931).