"Archived copy"(PDF). Archived from the original(PDF) on October 18, 2017. Retrieved October 17, 2017.{{cite web}}: CS1 maint: archived copy as title (link)
"USDA Plant Hardiness Zone Map". Agricultural Research Center, PRISM Climate Group Oregon State University. Archived from the original on February 27, 2014. Retrieved February 24, 2014.
"USDA Plant Hardiness Zone Map". Agricultural Research Center, PRISM Climate Group Oregon State University. Archived from the original on February 27, 2014. Retrieved February 24, 2014.
"Archived copy"(PDF). Archived from the original(PDF) on October 18, 2017. Retrieved October 17, 2017.{{cite web}}: CS1 maint: archived copy as title (link)