When searching HillCat, you can limit by collection to retrieve only children's books in print.
1. Select More Search Options
2. Under Collections highlight the Juvenile collections that you want to search (note that there are also Juvenile books in the Holocaust Collection).
3. To highlight more than one, press the Shift key as you are clicking on the collections.
3. Click on Set Search Options.
Ebook Central does not have children's books, but it does have items about children's literature.