Contribution to an evaluation of tree species using the new CITES Listing Criteria - WCMC (CITES, 1998)

Contributions from the Botanical Laboratory - University of Pennsylvania. Botanical Laboratory. (University of Pennsylvania Press, 1892)

Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania - University of Pennsylvania. Botanical Laboratory. ([s.n, 1934)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1891)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1902)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1903)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1905)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1911)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1917)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1921)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1923)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1924)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1925)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1927)

Contributions from the Gray Herbarium of Harvard University - Harvard University. Gray Herbarium. (Harvard University, 1928)