Specific reference for enforcement spot:
Rule 10 Enforcement of Penalties, Section 6 Enforcement Spots, All-But-One Principle
Unless otherwise listed in Section 4 and 5, a penalty for a foul occurring during a play is enforced from the basic spot with the exception of a foul by the offense which occurs behind the basic spot during a loose ball play or running play. This particular foul is enforced from the spot of the foul.
Also this "guidance" in the rule book after rule 10:
Enforcement philosophy is based on the fact that a team is given the advantage of the distance which is gained without assistance of a foul. It is assumed that the only foul which would give this aid is a foul by the offense behind the basic spot. Therefore, all fouls but this one, that is a foul by the offense behind the basic spot, are penalized from the basic spot unless the spot is otherwise specified by rule. This one foul is penalized from the spot of the foul. Whenever the ball is live, one of two types of plays is in progress, that is, either a loose-ball play or a running play.
