Resources, C. f. N. (2003, February). Species in Danger of Extinction. EDIS.
芝加哥风格引文Resources, Center for Natural. "Species in Danger of Extinction." EDIS Feb. 2003.
MLA引文Resources, Center for Natural. "Species in Danger of Extinction." EDIS, Feb. 2003.
警告：这些引文格式不一定是100％准确.