need four-node isoelement with given stiff matrix
 

I am making my code of In-Na-S and I used pressure correction method. Now I need an standard example like lid driven flow in a cavity. Can any body help to send me the standard example with given stiff-matrix? I need it to examine my expression of the pressure stiffness matrix. I can not find an example in that way(the books I can find) especilly for elleptic partial differential euqations. If you can please do me the favor (self-made of from book,and please send to tommewang@yahoo.com directly but do not tell book name only,I can not find any more books here). Thank alot.

or can you? please
 

Or any body can give me the stiff matrix of the following example (elleptic pde) d/dx(du/dx)+d/dy(du/dy)=f(x,y) x,y varies in a square cavity of unit length. f(x,y)=2./(delt**2)(at x=0.5 and y=0.5) or f(x,y)=0. at otherwhere. u(x,y)=0. at the four bouandaries thanks