Conn. Gen. Stat. § 52-206: Writings; admission of their execution.

(a) Either party to a civil action may, by a written notice, call upon the other to admit the existence and due execution of any document, material to the issue, saving all just exceptions.

(b) If the opposing party neglects or refuses to make such a requested admission within a reasonable time after the receipt of such notice, the costs of proving the document shall be paid by the party neglecting or refusing to make the admission regardless of the result of the action unless the court finds that the neglect or refusal was reasonable.