The format to follow is similar to a book chapter citation, for example, a poem from the edited collection, Seven Centuries of Poetry in English would look like this:
First footnote:
3. Seamus Heaney, "The Railway Children," Seven Centuries of Poetry in English, ed. John Leonard, 5th ed (Oxford University Press, 2003), lines 7-8.
Subsequent footnotes:
5. Heaney, "The Railway Children," 11.
Note: you can omit "line" or "lines" from the shortened footnote as long as the numbering you're using has been explained in the first footnote.
Bibliography:
Heaney, Seamus. "The Railway Children." Seven Centuries of Poetry in English, edited by John Leonard. 5th ed. Oxford University Press, 2003.
Further examples can be found in the complete Chicago Manual of Style - see links below.
