realgold

I dont know if it is published world wide but Ron Klinger's Bridge for Beginners is good in that there are exercises to do after each chapter to see if you have taken in what has been taught. Perhaps an idea for your young + pupils. Ron Klinger is an Australian and international bridge champion.

What is wrong with low to encourage, as you want to keep your high cards, and a higher card to discourage. or even odds and evens.