MLA

Carson, Rachel, 1907-1964. Biological controls. Box 30, folder 530-33. n.d.. https://collections.library.yale.edu/catalog/16845841.

APA, 6th edition

Carson, Rachel, 1907-1964. (["Box 30, folder 530-33"])(n.d.)[Biological controls]. https://collections.library.yale.edu/catalog/16845841.