convergent outer approximation method
approximation method of interval number
beeline approximation method
Butterworth approximation method
Chebyshev approximation method
curve approximation method
depreciation-appropriation method
diffusion approximation method
digital approximation method
dipole approximation method
discrete approximation method
discrete dipole approximation method
Eikonal approximation method
elliptic approximation method
Finite difference approximation method
first-order approximation method