Electronic books come in a variety of forms.  Some are accessed through our catalogs and databases and read over the Internet on a computer screen.  Others can be downloaded to a computer and in some cases to mobile devices. 

As the technologies of e-books are evolving, so are the formats for citing them in footnotes and bibliographies.  Here are guides to citing e-books in the three most common styles:

• APA (American Psychological Association) - see the section on "Electronic Books"
  
• MLA (Modern Language Association) - see the section on "Basic Style for Citations of Electronic Sources"
  
• Chicago - see the section on "Electronic Books and Books Consulted Online"

For more information, see:

• E-Books' Varied Formats Make Citations a Mess for Scholars (Chronicle of Higher Education)
• Find Books and E-books
• Citing Your Sources

Thanks to Purdue University for permission to use their citation guides.