Columbia subject headings:
Labor--Religious aspects--Islam--Nigeria, Northern.
Social classes--Nigeria, Northern.
Working class--Nigeria, Northern.
Harvard subject headings:
Labor--Religious aspects--Islam--Nigeria, Northern.
Social classes--Nigeria, Northern.
Working class--Nigeria, Northern.
Princeton subject headings:
Labor--Religious aspects--Islam--Nigeria, Northern.
Labor--Religious aspects--Islam.
Social classes--Nigeria, Northern.