image Chandrasekhar and Ferrari [59] have also reduced the time independent perturbation equations (using a different gauge) into a 5th order system which involves only the spacetime perturbations with the fluid perturbations being calculated via algebraic relations from the spacetime perturbations. It was later proven by Ipser and Price [112, 169] that this system of ODEs can be reduced to the standard equations in the Regge-Wheeler gauge. That this is possible is apparent from equations (51Popup Equation52Popup Equation53Popup Equation54Popup Equation) and it is discussed in [5]