Rubel Foundation. (1999). Perspectives in Plant Ecology, Evolution and Systematics. Urban & Fischer Verlag.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रRubel Foundation. Perspectives in Plant Ecology, Evolution and Systematics. Jena, Alemanha: Urban & Fischer Verlag, 1999.
एमएलए (8वां संस्करण) प्रशस्ति पत्रRubel Foundation. Perspectives in Plant Ecology, Evolution and Systematics. Urban & Fischer Verlag, 1999.
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