In stata, I regressed OLS (pannel data) by the following code:
reg lrgdpchlight lrgdpchWDI t* country*, cluster(iso_n) (iso_n =country)
t* is year fixed effect,
country* is country fixed effect.
I used cluster (by country) . However, I do not know how to do the same thing in R?
In R --> lm( y~x + factor(year) + factor(country) ) ----> how about include cluster((country) in R ?