U. S. Library of Congress. Photoduplication Service. (1950). Photoduplication service. Library of Congress.
芝加哥风格引文U. S. Library of Congress. Photoduplication Service. Photoduplication Service. Washington: Library of Congress, 1950.
MLA引文U. S. Library of Congress. Photoduplication Service. Photoduplication Service. Library of Congress, 1950.
警告：这些引文格式不一定是100％准确.