From No Limit Hold 'em: Theory and Practice by David Sklansky and Ed Miller.
Concept No. 34: If you have a close decision between semibluffing with a draw and checking it, be more inclined to check if you could make your draw with an overcard to the board.
Sklansky and Miller explain that if you make your draw with an overcard to the board, you might be able to win a big pot if your opponent happens to hit this card, too. I agree, but I don't like how this concept is presented. The discussion begins with the observation that "the higher implied odds your draw has, the less attractive semibluffing with it becomes." This is an important idea, and it would have made for a better "concept" than the one the authors chose. By semibluffing, you often eliminate your implied odds by ending the betting right away.
As it stands, Concept 34 describes a specific case of this idea. The authors not only missed this opportunity to put a particularly useful idea in their concepts, but they also failed to emphasize that the reader needs to be careful not to overgeneralize the advice given, which I think only holds in the specific case where you are deciding between semibluffing and checking. If you are deciding between semibluffing and betting, the opposite advice seems to hold: be more inclined to semibluff if you could make your draw with an overcard to the board.
The reason for this subtle distinction is that your implied odds only improve if an overcard is likely to help your opponent. This is generally only the case if your opponent has two overcards, which is unikely if you are thinking about calling (meaning your opponent has bet), because your opponent probably already has a pair. In this case, you would rather your draw be to undercards, because your opponent might be scared away by an overcard, thereby reducing your implied odds. In the case described by S+M, you are considering checking with your draw, meaning your opponent has not bet. So, it's a lot more likely that he his holding two overcards, and indeed it might help your implied odds if your draw included overcards to the board.
This is a little confusing, but I think the important insight is rather clear: "the higher implied odds your draw has, the less attractive semibluffing with it becomes."