Hardiness zones of the United States and Canada

Chicago citation style
Arnold Arboretum. Hardiness zones of the United States and Canada. 1948-07-01. Retrieved from the Digital Public Library of America, http://ark.digitalcommonwealth.org/ark:/50959/3j333722x. (Accessed July 23, 2018.)
APA citation style
Arnold Arboretum, (1948-07-01) Hardiness zones of the United States and Canada. Retrieved from the Digital Public Library of America, http://ark.digitalcommonwealth.org/ark:/50959/3j333722x
MLA citation style
Arnold Arboretum. Retrieved from the Digital Public Library of America <http://ark.digitalcommonwealth.org/ark:/50959/3j333722x>.
Note: These citations are programmatically generated and may be incomplete.