Columbia subject headings:
Excommunication--Islam.
Kufr (Islam)
Shīʻah--Doctrines.
Harvard subject headings:
Excommunication--Islam.
Kufr (Islam)
Shīʻah--Doctrines
Princeton subject headings:
Kufr (Islam)
Shīʻah--Doctrines.
Takfīr (Islam)