MLA

Mercator, Gerhard, 1512-1594, Ptolemy, 2nd cent. Tabvlae geographicae Cl: Ptolemei ad mentem autoris restitutae & emendate per Gerardum Mercatorem .... 1578]. https://collections.library.yale.edu/catalog/11788354.

APA, 6th edition

Mercator, Gerhard, 1512-1594, & Ptolemy, 2nd cent. (1578])[Tabvlae geographicae Cl: Ptolemei ad mentem autoris restitutae & emendate per Gerardum Mercatorem ...]. https://collections.library.yale.edu/catalog/11788354.