Ancient Greek works like Aristotle's "Poetics" require no reference-page entry, so the in-text citation gives more detail about the specific source. The first reference to the work should give the title of the "Poetics" in a signal phrase so the reader knows what work you are referring to, like this: "As explained in Aristotle's 'Poetics,' ...." As with any source, the parenthetical citation should give the author's name. But a reference to the "Poetics" should also include the date of the translation you referenced, preceded by "trans." -- without the quotation marks -- instead of Aristotle's original publication date, since the first publication date is unknown: (Aristotle, trans. 1975). This detail helps readers find the version you quote or paraphrase in your paper. If you cite a particular portion of the piece, include some detail to help the reader find the passage. Since the "Poetics" appears in sections, a section number is appropriate. For instance, (Aristotle, trans. 1975, II) indicates a 1975 translation of Aristotle's work, section two.