Não informado. (1933). Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania. University of Pennsylvania.
Čikaški stil citiranja (17. izdanje)Não informado. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania. Philadelphia, Pa: University of Pennsylvania, 1933.
MLA način citiranja (8. izdanje)Não informado. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania. University of Pennsylvania, 1933.
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