Ray, R. B. (2012). Walden x 40: Essays on Thoreau. Indiana University Press.
芝加哥风格引文Ray, Robert B. Walden X 40: Essays on Thoreau. Bloomington, Ind.: Indiana University Press, 2012.
MLA引文Ray, Robert B. Walden X 40: Essays on Thoreau. Indiana University Press, 2012.
警告：这些引文格式不一定是100％准确.