What Catholic School Text Book has Obama Been Reading?

Obama gave his nobel peace prize acceptance speech today.  Beside the numerous logical fallacies in his speech, what caught my attention in his speech was the mention of "just war".  He doesn't call it a theory, so I'm wondering from what poorly written catholic high school text book was he quoting?


Here is the quote:

Over time, as codes of law sought to control violence within groups, so did philosophers, clerics, and statesmen seek to regulate the destructive power of war. The concept of a "just war" emerged, suggesting that war is justified only when it meets certain preconditions: if it is waged as a last resort or in self-defense; if the forced used is proportional, and if, whenever possible, civilians are spared from violence.