Co NP problem correponding to SAT I've been reading lately about SAT problem, NP and co-NP. 

Many sources say that the SAT problem is co NP, though, I can't find a co-NP problem equivalent to SAT. 

Does anyone have any idea about this ? (Or could lighten my misunderstandings)
If SAT is in coNP then NP=coNP, which is believed to be false. However, coSAT, the language of unsatisfiable CNFs, is coNP-complete.