India. Registrar General and ex-officio Census Commissioner & Sekhar, A. C. (1968). Census of India, 1961: Economic regionalization of India: problems and approaches. s.n.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रIndia. Registrar General and ex-officio Census Commissioner और A. Chandra Sekhar. Census of India, 1961: Economic Regionalization of India: Problems and Approaches. s.n, 1968.
एमएलए (9वां संस्करण) प्रशस्ति पत्रIndia. Registrar General and ex-officio Census Commissioner और A. Chandra Sekhar. Census of India, 1961: Economic Regionalization of India: Problems and Approaches. s.n, 1968.
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