MLA

Columbus, Christopher, Hammer, Heinrich, active 1480-1496, cartographer, Rosselli, Francesco di Lorenzo, 1445-1513. Map of the world of Christopher Columbus.. ca. 1489. https://collections.library.yale.edu/catalog/2007580.

APA, 6th edition

Columbus, Christopher, & Hammer, Heinrich, active 1480-1496, cartographer, & Rosselli, Francesco di Lorenzo, 1445-1513. (ca. 1489)[Map of the world of Christopher Columbus.]. https://collections.library.yale.edu/catalog/2007580.