Some poetic works are conventionally referred to using an established numbering system that allows readers using any edition of the work to easily locate the cited material. If a single poem from an anthology is being cited, the number can be given in the Title of Source element of the works-cited-list entry:
Shakespeare shows how memories of grief and loss can all too easily dominate “the sessions of sweet silent thought” if not counterbalanced by the recollection of joy.
Work Cited
Shakespeare, William. Sonnet 30. The Norton Anthology of English Literature, M. H. Abrams, general editor, 6th ed., vol. 1, W. W. Norton, 1993, p. 812.
When the numbered poem occurs in a titled poem cycle (frequently excerpted in anthologies), the cycle can be named in the Title of Source element, and individual poems can be identified by number as needed in your prose or in-text citations:
In sonnet 75, the poet vows to immortalize his love by writing it “in the heavens” (Spenser 737).
Work Cited
Spenser, Edmund. Excerpt from Amoretti. The Norton Anthology of English Literature, M. H. Abrams, general editor, 6th ed., vol. 1, W. W. Norton, 1993, pp. 734–38.
Read more on citing excerpts and other works in anthologies.