Britannica is a fantastic resource. This link is set for "Level 3," meaning it has the most detail. You can also check level 2 or 1 for a quicker, but less thorough, read. Remember that Britannica will make a citation for you. Just click the checkbox at the top right of the page.
Middle School In Context has many different resources for you. This link will take you to reference articles about the religion you are researching. Remember that you can use the "cite" button to have your citation made for you or exported directly into NoodleTools.
Salem Press Encyclopedia
This reference resource includes a useful article on the Native American Church.