Pike's Peak Trail
MLA
Ingersoll, Ernest, 1852-1946, Jackson, William Henry, 1843-1942. Pike's Peak Trail. https://collections.library.yale.edu/catalog/2018677.
APA, 6th edition
Ingersoll, Ernest, 1852-1946, & Jackson, William Henry, 1843-1942. [Pike's Peak Trail]. https://collections.library.yale.edu/catalog/2018677.