MLA

Walpole, Horace, 1717-1797, author. Mr. Walpole is very ready to oblige any curious persons with the sight of his house and collection .... [1789?]. https://collections.library.yale.edu/catalog/33485790.

APA, 6th edition

Walpole, Horace, 1717-1797, author. ([1789?])[Mr. Walpole is very ready to oblige any curious persons with the sight of his house and collection ...]. https://collections.library.yale.edu/catalog/33485790.