1. Henrici, P.: Discrete variable methods. New York: Wiley 1962.
2. Gragg, W.: Repeated extrapolation to the limit in the numerical solution of ordinary differential equations. Thesis UCLA (1963)
3. Fehlberg, E.: Runge-Kutta type formulas of high-order accuracy and their application to the numerical integration of the restricted problem of three bodies. Colloque international des Techniques de Calcul Analogique et Numérique en Aéronautique à Liège, 1963
4. — New high-order Runge-Kutta formulas with an arbitrarily small truncation error. To appear in ZAMM 45, (1965)
5. Filippi, S.: Angenäherte Lösung eines astronomischen Drei-Körperproblems. Teil II. Elektronische Datenverarbeitung, Heft 6, 264–268 (1963)