Não informado. (1933). Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania. University of Pennsylvania.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania. Philadelphia, Pa: University of Pennsylvania, 1933.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania. University of Pennsylvania, 1933.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.