(1968). Populations: A science unit for the primary grades (Trial ed.). Science Curriculum Improvement Study.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रPopulations: A Science Unit for the Primary Grades. Trial ed. Berkeley, CA: Science Curriculum Improvement Study, 1968.
एमएलए (9वां संस्करण) प्रशस्ति पत्रPopulations: A Science Unit for the Primary Grades. Trial ed. Science Curriculum Improvement Study, 1968.
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