Discipline for dogs who mess in the house....?

The books you are reading are correct. The best way to get them trained is to praise them when they do it correctly, not punish them when they don't. NEVER hit a dog - this will just cause aggression issues. And the books are correct when they say the dog has already forgotten by the time you find it. If you catch them while they are doing it just give them a stern NO so they know they did something wrong and then take them directly outside so they learn the proper place to go. Good luck!