The choice of shoes for children is crucial to the development of a health foot structure and not causing problems The growing foot is malleable and easily deformed by incorrectly fitting footwear. The general advice is that shoes should not inhibit or interfere with normal development of the foot.
https://podiatryarena.com/index.php?articles/best-advice-for-shoes-for-children.7/ (Podiatry Arena)
https://podiatryarena.com/index.php?threads/should-small-children-have-shoes.730/ (Podiatry Arena)
http://www.podiatryonline.tv/childrens-footwear.htm (Podiatry TV)
http://www.childrensshooz.com/ (Children Shooz)
http://www.kidshooz.com/ (Kids Shooz)
http://www.itsafootcaptain.com/the-apma-are-taking-some-heat-for-this-advice-on-childrens-shoes-and-its-hard-to-defend/ (Its a Foot Captain)