MacDonald Hall books

Hello Mr. Korman,

You are one of my three sons’ favorite all time authors. Long ago, after a reading you did at the Dolphin Book Shop in Port Washington, I tracked down a box set of the MacDonald Hall books. They have been very well-loved and well-read. I would love to purchase a set for my nephew who is in 4th grade. Do you have any idea where to purchase the set? Thank you.