MLA

Virtuous Royalty. : A Tear of Respect to the Memory of a Generous & Patriotic Prince, and to a Beloved but Not Forgotten Princess, and of Sympathy to the Bereaved Royal Survivors. Engraved & published 23rd March 1820 by Jas. Debaufer, 11 Creed Lane, Ludgate Street, 0AD. https://collections.library.yale.edu/catalog/33111691.

APA, 6th edition

Virtuous royalty. : A tear of respect to the memory of a generous & patriotic prince, and to a beloved but not forgotten princess, and of sympathy to the bereaved royal survivors. (0 C.E.). [Poetry, Poems, Memorial works, Broadside poems, Engravings England London 1820]. Engraved & published 23rd March 1820 by Jas. Debaufer, 11 Creed Lane, Ludgate Street. https://collections.library.yale.edu/catalog/33111691.