Okay so I'm new to Pathfinder and have only done 9 sessions of DM'ing and 1 session of playing so far. We've always played as if you can crit again while rolling for confirming a critical (my players learned me the basic rules and then I've basically used d20pfsrd or asked them if I had any questions). But I can't find anything about this (don't own the books), and googling gave me nothing except that you couldn't do it in 3.5. But my player said it's in the core rulebook, but since I don't own it I can't look, I just think it would say so on d20pfsrd if you could.
So basically: Can you crit again while confirming a critical? Or have we played wrong all the time? Also, if you can do it, please link me to the rule saying where you can (or a rule/anything saying opposite if there is one).