Columbia subject headings:
Abū Bakr, Caliph, -634.
Caliphs--Biography.
Riddah Wars.
Harvard subject headings:
Abū Bakr, Caliph, -634.
Caliphs--Biography.
Riddah Wars.
Princeton subject headings:
Abū Bakr, Caliph, -634.
Caliphs--Biography.
Riddah Wars.