Cite

"Another Matterhorn Catastrophe."

MLA

Hansen, Bert, 1944-. "Another Matterhorn Catastrophe.". Box 8, folder 30. 1881 July 6. https://collections.library.yale.edu/catalog/32327086.

APA, 6th edition

Hansen, Bert, 1944-. (["Box 8, folder 30"])(1881 July 6)["Another Matterhorn Catastrophe."]. https://collections.library.yale.edu/catalog/32327086.