I was looking for a reasonably recent discussion of social identity theory, and found Part I of this book:
McKeown, Shelley, Reeshma Haji, and Neil Ferguson. "Understanding peace and conflict through social identity theory." Contemporary Global Perspectives. Switzerland: Springer (2016).
If you're interested in issues of peace and conflict, this field of scholarship is probably relevant.
#SocialIdentityTheory #SocialPsychology #GroupRelations