As part of an investigation of flows around and forces on an oscillating finite wing in subsonic compressible flow, the exact double integrals occurring in the theoretical formulation of the three-dimensional nonstationary aerodynamic forces have previously been reduced to single integrals over the range of either one of the two independent variables. The present report describes a method for solving the resultant three-dimensional problem based on a generalization of approximate methods for solving two-dimensional problems. It is shown that the calculation of three-dimensional corrections to the two-dimensional integral equation for spanwise variation of circulation, provided tabulated values for the kernal of the integral equation are available.