Can someone please assist!!!

I have an unbalanced panel data, 145802 observations for about 35432 firms in total. I need to estimate firm level TFP.
Does anyone know the approach and command/s to use?

Any help/hint will be much appreciated
Thanks, fzahra
although i'm not familiar with economics stats, a quick search on "google" gave several results which might help you.
a relevant one can be found at ""
or ""