Rules of Golf 2012-2015 Pocket Edition - The R&A

Rule 20 87
If a competitor becomes aware that he has played from a wrong place and
believes that he may have committed a serious breach, he must, before
making a stroke on the next teeing ground, play out the hole with a second
ball played in accordance with the Rules. If the hole being played is the last
hole of the round, he must declare, before leaving the putting green, that he
will play out the hole with a second ball played in accordance with the Rules.
If the competitor has played a second ball, he must report the facts to
the Committee before returning his score card; if he fails to do so, he is
disqualified. The Committee must determine whether the competitor has
committed a serious breach of the applicable Rule. If he has, the score with
the second ball counts and the competitor must add two penalty strokes
to his score with that ball. If the competitor has committed a serious breach
and has failed to correct it as outlined above, he is disqualified.
Note 1: A competitor is deemed to have committed a serious breach of
the applicable Rule if the Committee considers he has gained a significant
advantage as a result of playing from a wrong place.
Note 2: If a competitor plays a second ball under Rule 20-7c and it is ruled
not to count, strokes made with that ball and penalty strokes incurred solely
by playing that ball are disregarded. If the second ball is ruled to count, the
stroke made from the wrong place and any strokes subsequently taken with
the original ball including penalty strokes incurred solely by playing that ball
are disregarded.
Note 3: If a player incurs a penalty for making a stroke from a wrong place,
there is no additional penalty for:
(a) substituting a ball when not permitted;
(b) dropping a ball when the Rules require it to be placed, or placing a ball
when the Rules require it to be dropped;
(c) dropping a ball in an improper manner; or
(d) a ball being put into play by a person not permitted to do so under
the Rules.