Scale ca. 1:250,000. Folded title: Big Bend. Relief shown by shading and spot heights. "Reprint 1978." Includes text. Insets: The Basin.--Rio Grande Village. Text and col. ill. on verso. Available also through the Library of Congress Web site as a raster image. AACR2
United States. National Park Service
<a rel="nofollow" class="external free" href="https://www.loc.gov/item/78694294/">https://www.loc.gov/item/78694294/</a>