[1] Apostol, T. M., Calculus, vol. 1, 2nd ed., John Wiley & Sons, New York, 1967.
[2] Apostol, T. M., Mnatsakanian, M. A., Surprising geometric properties of exponential functions,
Math Horizons, (1998), 27–29.
[3] Apostol, T. M., Mnatsakanian, M. A., Subtangents—an aid to visual calculus, Amer. Math. Monthly,
109 (2002), 525–533.
[4] Apostol, T. M., Mnatsakanian, M. A., Tangents and subtangents used to calculate area, Amer. Math.
Monthly, 109 (2002), 900–909.
[5] Hamilton, W. R., The hodograph, or a new method of expressing in symbolic language the Newtonian
law of attraction, Math. Proc. R. Ir. Acad., 3 (1847), 344–353.
[6] Withers, L., Mamikon meets Kepler, email dated April 21, 2009.
)