RESPONSES TO A 2NT OR 3NT OPENING
SSS by Danny Kleinman

SAYC. Gerber (over 2NT only), Stayman and Jacoby apply. No meaning at all is assigned to responses in spades.

SSS. It's a shame not to have ways to look for minor suit slams. The 1NT structure applies virtually unchanged, one or two levels higher.  However, a 2NT bidder should treat a Jacoby Transfer as mildly invitational to four of responder's major, and jump-accept with 4-card support if he'd feel unhappy to be passed in 3H or 3S.