During most of the 1960s he studied the equilibrium and the stability of ellipsoidal figures of equilibrium but during this period he also began work on topics from general relativity, the radiation reaction process, and the stability of relativistic stars.
Sa panahon ng karamihan ng 1960s-aral siya ng balanse at ang katatagan ng ellipsoidal numero ng balanse ngunit panahon na ito siya rin ay nagsimulang magtrabaho sa paksa mula sa pangkalahatang kapamanggitan, ang radiation reaksyon proseso, at ang katatagan ng relativistic stars.