MLA

Homann Erben (Firm), Mayer, Tobias, 1723-1762. Helvetia tredecim statibvs liberis, quos cantones vocant composita: una cum foederatis & subjectis provinciis, ex probatissimis subsidiis. ca. 1751. https://collections.library.yale.edu/catalog/2065586.

APA, 6th edition

Homann Erben (Firm), & Mayer, Tobias, 1723-1762. (ca. 1751)[Helvetia tredecim statibvs liberis, quos cantones vocant composita: una cum foederatis & subjectis provinciis, ex probatissimis subsidiis]. https://collections.library.yale.edu/catalog/2065586.