Ferengi Rules Of Acquisition: Number 76: "Every once in a while, declare peace. It confuses the hell out of your enemies."
Li Nalas: Halfway down the embankment, I slipped and went sprawling on my back, down to the edge of the lake, just as a huge Cardassian emerged from the water. He must have just finished bathing. He stood there frozen in surprise, dressed only in his underwear, shivering from the cold. I lay there, looking up at him, too stunned to even move. It was only when he reached for a phaser rifle that was lying across his clothes on a nearby rock, that I realized I was still holding my own phaser. And I shot him - his body fell on top of me, and that's how my companions found us a moment later... I'll never forget that look on his face when he died. He was so... embarrassed!
Sisko: You're too young to take a girl to the holo-suites.
Jake: Ok. Then how about if I take her to our quarters?
Sisko: Oh, no, no, no. No quarters.
Sisko: I already have a liaison officer.
Jaro: Not anymore, you don't. Major Kira is no longer assigned to this post. She's been recalled to Bajor.
Frank Langella was not credited for his appearance in the "Circle" storyline.
The part about the POW's is an allusion to the long time belief that there were still prisoners of war left in Vietnam even years (decades even) after the war there was over.
It is the first mention of prisoners left after Cardassian occupation... and they swore they had no more prisoners.