You find or you are given a reference list (see below for example), with a list of journal articles that you want to find:
Now you pick out which of the References are book titles and which are journal titles.
#21 is a book title, you can see that by noticing it does not include a volume #, issue # or page number (look @ #'s 1 and 2 for examples). Exception: some books will give page numbers if they are citing from an Anthology with multiple authors, but they still will not include a volume # or issue #.
