Tolman-Oppenheimer-Volkoff Equations in Modified Gauss-Bonnet Gravity
  Based on a stringy inspired Gauss-Bonnet (GB) modification of classical gravity, we constructed a model for neutron stars. We derived the modified forms of Tolman-Oppenheimer-Volkoff (TOV) equations for a generic function of $f(G)$ gravity. The hydrostatic equations remained unchanged but the dynamical equations for metric functions are modified due to the effects of GB term. 
D. Momeni, R. Myrzakulov
gr-qc astro-ph.HE hep-th