MLA

Clark, William, 1770-1838. Area of the junction of the Medicine (Sun) and Missouri rivers and sketches of the falls of the Missouri, route about June-July 1805. Box 1, folder 25v. circa 1803-1810. https://collections.library.yale.edu/catalog/2002471.

APA, 6th edition

Clark, William, 1770-1838. (["Box 1, folder 25v"])(circa 1803-1810)[Area of the junction of the Medicine (Sun) and Missouri rivers and sketches of the falls of the Missouri, route about June-July 1805]. https://collections.library.yale.edu/catalog/2002471.