APA (7th ed.) Citation

(1960). Plant hardiness zone map. U.S. Dep. of Agriculture.

Chicago Style (17th ed.) Citation

Plant Hardiness Zone Map. Washington: U.S. Dep. of Agriculture, 1960.

MLA (9th ed.) Citation

Plant Hardiness Zone Map. U.S. Dep. of Agriculture, 1960.

Warning: These citations may not always be 100% accurate.