I need reliable internet sources on Halloween.
That is a very broad topic, so you might need to narrow that down.
First, go to the library homepage, linked below. In the big center box, you will see a link to Britannica. Click on that link, and search for Halloween.
For some good internet sources, go to the History Channel link below, and some general information posted by the University of Albany. At the very bottom of that page are links to their sources.