Abs problems ?!

Abs problems ?

I have a problem in making my six pack more lean and even. Since i was high 1 i already had a six pack but i never could making it equally big. my right side abs seems to be smaller than the left and my upper abs are incredibly small compare to the mid and lower abs...

my question : Is there a way in making it even ? (please indicate how many sets and reps i should do )

a link would be greatly appreciated..

thanks :D

medical/scientific approach (recccommended)- exrx.net

other approach- bodybuilding.com

dude crunches work mostly the upper abs, do those. most people have the opposite problem