Adding control variables

The stock of domestic R&D is a hard to get and valuable variable in the case of developing nations. On top of that I have to collect some data, measures of human capital…of which I opted for the world wide known Barro and Lee 2000 dataset and perhaps some other schooling stuff from UIS Unesco and the WID 20007.
I already used the BL 2000 and the tertiary enrollment and they seem to impact significantly the TFP spillovers, which is good. :)