APA

University of Pennsylvania, . (1892). Contribution from the Botanical Laboratory of the University of Pennsylvania. Philadelphia: University of Pennsylvania.

Chicago

University of Pennsylvania, . 1892. Contribution from the Botanical Laboratory of the University of Pennsylvania. Philadelphia: University of Pennsylvania.

Harvard

University of Pennsylvania, . (1892). Contribution from the Botanical Laboratory of the University of Pennsylvania. Philadelphia: University of Pennsylvania.

MLA

University of Pennsylvania, . Contribution from the Botanical Laboratory of the University of Pennsylvania. Philadelphia: University of Pennsylvania. 1892.