Columbia subject headings:
Harvard subject headings:
Concord--Religious aspects--Islam
Islam--Unity
Islamic law.
Shīʻah--Relations--Sunnites.
Sunnites--Relation--Shiites.
Princeton subject headings:
Concord--Religious aspects--Islam.
Islam--Unity.
Islamic law.
Shīʻah--Relations--Sunnites.
Sunnites--Relation--Shiites.