Does anyone know of some good books to read to toddlers on following the rules?

I am an Early Childhood Behavioral Counselor, and I am working on a curriculum to teach my group about following the rules. I have some good games that they can play for practice; however, I need something that will engage them in the Psycho-education. Usually a good book can help, but I'm stuck. I cannot seem to find a good one that is going to go into depth, but be simplistic enough for 3-4 year old children. Do any of you have any suggestions? Thank you!