APA style dictates that the references page should be double-spaced, and that entries should be formatted with a hanging indent. A hanging indent is formatted so that the first line of each entry is at the left margin and subsequent lines in the same entry should be indented.
For titles starting with articles ("a" and "the"; and equivalents in other languages), the article is not considered when alphabetizing. Numerals and numbers are alphabetized as though they are spelled out.
In APA style, every reference cited in your text must be reflected in an entry on your references page. The only exceptions to this rule are personal communications with the author such as e-mails, conversations, and letters which need only be cited in text. Likewise, every item on the references page must correspond to an in-text citation somewhere in your work. Do not include works that you do not cite in the body of your paper.