If your assignment requires you to look up background information, World Book is the place to find it. Think of it like an academic Wikipedia.
Rather than thinking of it as using them separately, use them together. Wikipedia is great for convenience and generally being readable. However, the articles on Wikipedia are editable by anyone who has access to the internet and, therefore, could be subject to inaccuracies which would lead to your work being inaccurate. World Book edits its articles quite meticulously and is written for students which means that content and writing level is appropriate for your reading level.
I would search Wikipedia first in order to get a quick answer and if you find the exact same information on World Book, you know its accurate. Then, cite World Book.
Yes! It will ask you for a login and password.
Login: knights
Password: edmundian