APA (7th ed.) Citation

Thoreau, H. D., Curtis, G. W., & Hill, E. B. Henry D. Thoreau to George William Curtis ..

Chicago Style (17th ed.) Citation

Thoreau, Henry David, George William Curtis, and Edwin Bliss Hill. Henry D. Thoreau to George William Curtis ..

MLA (9th ed.) Citation

Thoreau, Henry David, et al. Henry D. Thoreau to George William Curtis ..