I've been making and publishing preschool activity books - things like basic math and learning to print. I wanted to branch out and include more information - such as an activity book that includes facts about insects, for example. I would need to do research (proper book research, not wikipedia) to find the facts to put in the activity book. I've been having trouble finding articles on-line about how to do this. I understand I would include a bibliography if I was submitting this as a project to a publisher, but what about self-publishing? I never see a bibliography included in the actual books I've looked at.