Correct contract bridge / by E.V. Shepard ; including the official Laws of contract bridge adopted by the Whist Club, New York, and by all the leading clubs in America.

230 CORRECT CONTRACT BRIDGE
(f) If an adversary who has played to the
twelfth trick, shows his thirteenth card
before his partner plays his twelfth,
the partner's two cards are exposed.
(g) If an adversary throw his cards face up on
the table, they are exposed, unless such
act follows a claim by Declarer of a
certain number, or the rest of the tricks.
(h) A card designated by any law as
"exposed."
PENALTY FOR EXPOSED CARDS
33. (a) There is no penalty for a card exposed
by Declarer or Dummy.
(b) A card exposed by an adversary must be
left face up on the table and Declarer may call it
(i. e., require its owner to lead or play it) whenever it is the owner's turn to lead or play, unless
playing it would cause a renounce.
(c) Declarer may not prohibit the lead or play
of an exposed card, and its owner may lead or play
it whenever he legally can do so: but until played,
Declarer may call it any number of times.
LEADS OUT OF TURN AND CARDS
PLAYED IN ERROR
34. (a) After the contracting ends and before
Senior leads, should Junior lead or expose a card,
Declarer may treat it as exposed, or require Senior
(the proper leader) to lead a card of a suit named
by Declarer. Dummy may call attention to the offense; but should Declarer and Dummy consult regarding the penalty, it is canceled. Should Dummy