Cite

[A study of proportions] [art original].

MLA

[A Study of Proportions] [Art Original]. 0AD. https://collections.library.yale.edu/catalog/17338421.

APA, 6th edition

[A study of proportions] [art original]. (0 C.E.). [Ink drawings, Drawings]. https://collections.library.yale.edu/catalog/17338421.