Surveyor's certificate in Thoreau's hand
MLA
Thoreau, Henry David, 1817-1862. Surveyor's certificate in Thoreau's hand. Box 1, folder 16. 1850 Aug 15. https://collections.library.yale.edu/catalog/2056837.
APA, 6th edition
Thoreau, Henry David, 1817-1862. (["Box 1, folder 16"])(1850 Aug 15)[Surveyor's certificate in Thoreau's hand]. https://collections.library.yale.edu/catalog/2056837.