MLA

Darby, William, 1775-1854. Map of the state of Louisiana : with part of the Mississippi Territory, from actual survey / by Wm. Darby ; Saml. Harrison sct. Philaa.. BRBL_00521. May the 1st, 1816.. https://collections.library.yale.edu/catalog/15811425.

APA, 6th edition

Darby, William, 1775-1854. (["BRBL_00521"])(May the 1st, 1816.)[Map of the state of Louisiana : with part of the Mississippi Territory, from actual survey / by Wm. Darby ; Saml. Harrison sct. Philaa.]. https://collections.library.yale.edu/catalog/15811425.