How would you handle this in your ebook? Do I need permission from the AAP? Lead the reader to those sources (e.g. "To see the notable milestones for a 6 month old baby, visit the AAP site at...").
These aren't exactly a focus for the guide, but will be helpful for the parents to know in reading the other information.
I don't think I've ever seen an ebook with references...
I'm not sure how to handle it.