1. An Osculatory Extension of Cauchy's Rational Interpolation Formula
2. Vorlesungen über Differenzenrechnung, Berlin, Julius Springer 1924.
3. The Calculus of Finite Differences, Macmillan, London 1933, pp. 34–35.
4. Calculus of Finite Differences, 2nd ed., Chelsea, New York 1947, pp. 96–97.
5. A Treatise on the Calculus of Finite Differences, 1st. ed., 1860; information obtained from 3rd ed., G. E. Stechert, New York, 1946, pp. 20 to 21.