difference in difference
difference in difference (DD) method
Difference-in-difference
+ expression difference
27-point difference sheme
2kL method of the optical-path difference
2nd-order difference ARED
3-bands grads difference method
3-D explicit finite difference
3D finite difference method
3D finite difference migration
3-point and 5-point difference schemes
9-point difference scheme
a difference equation of single-species
a distinction without a difference
a new finite difference form