2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54231A discussion of the number of degrees of freedom, and their dynamical properties, in higher derivative gravitational theories is presented. It is shown that non-vanishing $(C_{mnpq})^{2}$ terms arise in N=1, D=4 superstring Lagrangians due to one-loop radiative corrections with light field internal lines.Talk presented at STRINGS'95, University of Southern California, Los Angeles, CA, March 13-18, 1995; 6 pages, latexHigh Energy Physics - Theorytext