Book by Ribes and Zalesskii, in Group theory folder.
Serre: Galois cohomology
Cohomology of number fields?
Profinite Groups, Second edition (Ergebnisse der Mathematik und ihrer Grenzgebiete. 3. Folge / A Series of Modern Surveys in Mathematics) fra Mathematics by: Luis Ribes, Pavel Zalesskii
nLab page on Profinite groups