Não informado. (1970). Current sweden: Environment planning and conservation. Swedish Institute.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Current Sweden: Environment Planning and Conservation. Stockholm: Swedish Institute, 1970.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Current Sweden: Environment Planning and Conservation. Swedish Institute, 1970.
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