MLA

Gilbert, W. S. (William Schwenck), 1836-1911. An entirely new and original aesthetic opera : in two acts, entitled Patience, or, Bunthornes bride. [1881?]. https://collections.library.yale.edu/catalog/2020477.

APA, 6th edition

Gilbert, W. S. (William Schwenck), 1836-1911. ([1881?])[An entirely new and original aesthetic opera : in two acts, entitled Patience, or, Bunthornes bride]. https://collections.library.yale.edu/catalog/2020477.