MLA

Grignion, Charles, 1721-1810, printmaker. Vetvs aqvilae signvm marmorevm operis eximii anno MDCCXXXXII idibvs Octobris Romae prope thermas Antoninianas in hortis Bvccapadvliis ad radices aventini effossvm : nvnc in aedibvs Horatii Walpole Londini / [graphic]. [1755]. https://collections.library.yale.edu/catalog/16193138.

APA, 6th edition

Grignion, Charles, 1721-1810, printmaker. ([1755])[Vetvs aqvilae signvm marmorevm operis eximii anno MDCCXXXXII idibvs Octobris Romae prope thermas Antoninianas in hortis Bvccapadvliis ad radices aventini effossvm : nvnc in aedibvs Horatii Walpole Londini / [graphic]]. https://collections.library.yale.edu/catalog/16193138.