The reference books will give you an overview of your subject. Use the table of contents or index to find the information you are looking for. If you can't find it, try to think of alternate names or spellings and look there.
Right: Palenque. Jorge Pérez De Lara. Ancient and Medieval History Online. Web. 13 Sept. 2016. http://online.infobase.com/HRC/Search/ImageDetails/7?imageId=43357.
Here's a list of selected specialized reference books (available in the Garver Room) you may want to consider.
Remember, reference books CANNOT be checked out or leave the library. When you are done using them, please return reference books to the cart near the entrance to the Garver Room.