I want to include a line from a famous poem in a prose piece. I give credit and it's a short line. I don't know if it makes a difference, but the poem is really old. However, it is quite appropriate for the piece I'm working on. Can I do this or how can I do this? My piece will be published. That's already lined up. I just don't want to make an amateur mistake or look stupid. Literary criticism obviously addresses these sort of issues. However, this sort of writing is a bit new for me, and I'm not sure where all the lines are. Don't want to cross the wrong ones. I know people often say you can't quote things without permission, but when it comes to literary criticism it seems the rules are quite different, no? Any and all thoughts about handling these sort of situations are much appreciated. Thanks.