Restriction on Coeffi of 3 pooling equations

[atomictatu]

I have a pool set (10 years, 3 variables X Y Z, 20 cross-section). The model is like:

Y=a+b*X+u
Z=c+d*X+v

I have estimated the two equations seperatly by pooling, but the point is that I need to put a restriction like b+d=c, c is a constant, but I dont know how ..

can anyone help me.......

Many Thx!

[EViews Gareth]

Assuming you're doing simple least squares you could Convert the pool to a panel, then use the system object to estimate the equations