Valkenberg. Renewing Islam by Service. The Catholic University of America Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रValkenberg. Renewing Islam by Service. The Catholic University of America Press.
एमएलए (9वां संस्करण) प्रशस्ति पत्रValkenberg. Renewing Islam by Service. The Catholic University of America Press.
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