APA (7 वां संस्करण) प्रशस्ति पत्र

Penjerdel (Corporation). (1961). Historical development of local government in the Penjerdel region. Pennsylvania Economy League (Eastern Division).

शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र

Penjerdel (Corporation). Historical Development of Local Government in the Penjerdel Region. Philadelphia?: Pennsylvania Economy League (Eastern Division), 1961.

एमएलए (8वां संस्करण) प्रशस्ति पत्र

Penjerdel (Corporation). Historical Development of Local Government in the Penjerdel Region. Pennsylvania Economy League (Eastern Division), 1961.