From post: "Rather than add page numbers that don’t correspond to print books, which is how page numbers have been added to e-books in the past, we’re adding real page numbers that correspond directly to a book’s print edition."
There is still some confusion regarding how to cite eBook Readers.
"As e-reading devices gain popularity, professors and students are struggling to adapt them to an academic fundamental: proper citations, which other scholars can use. The trouble is that in electronic formats, there are no fixed pages." (Tushar Rae, "E-Books' Varied Formats Make Citations a Mess for Scholars: Kindle, Nook, and other devices put the same text on different pages," Chronicle of Higher Education, Feb. 6, 2011)
What is common to all citation formats is that the goal remains the same: have enough information so someone else can find it. Check with your citation guide's publications (books, websites, newsletters, blogs) to find out what's being said about e-Readers as some of them may have informally published guidelines to follow while others may offer suggestions.
When in doubt, ask your professor!
If you are the professor and you are still in doubt, then contact the publication to which you are submitting your paper. If you are just giving your students advice, and there is no information available on any of your guides' websites, RSS feeds, etc., then you can either make your own rules (it is your class!) or have your students think about what is important and necessary in order to be able to find that particular resource again.
Include the type of e-book version (for instance, Kindle DX). Include the DOI if provided; if not provided, indicate where the e-book was downloaded.
Schiraldi, G. R. (2001). The post-traumatic stress disorder sourcebook: A guide to healing, recovery, and growth [Adobe Digital Editions version]. doi:10.1036/0071393722
Shotten, M. A. (1989). Computer addiction? A study of computer dependency [DX Reader version]. Retrieved from http://www.ebookstore.tandf.co.uk/html/index.asp
For parenthetical references that would normally include page numbers, if the e-reader version of the e-book does not provide page numbers, use the paragraph number, heading, or similar that is provided. Examples: (para. 4), (Discussion section, para. 1).
For more details, consult the APA Publication Manual, 6th ed., Chapter 7 (examples 19, 20, and 21) and Chapter 6 (section 05). The Manual can be borrowed from the Reference Desk on the second floor of the Library.
In general, follow the same guidelines you would follow for an ordinary book, then include the file type of the e-book (for example, Kindle file, EPUB file, PDF file, etc.). If you can't identify a particular file type, use Digital file.
Slawenski, Kenneth. J.D. Salinger: A Life. New York: Random, 2011. N. pag. EPUB file.
For parenthetical references that would normally include a page number, if the e-reader version of the e-book does not contain page numbers, use the paragraph or section number provided and indicate it with the appropriate abbreviation, such as: par. 41
For more details, consult the MLA Handbook for Writers of Research Papers, 7th ed., sections 5.7.18 and 6.4.2. The Handbook can be borrowed from the Reference Desk on the second floor of the Library.
Further info: MLA.org, "How do I cite an e-book?" http://www.mla.org/style/style_faq/mlastyle_cite_an_ebook
Generally follow the format for a book, but include the format consulted at the end (for example, Kindle edition, Microsoft Reader e-book, Palm e-book, PDF e-book, etc.).
Austen, Jane. Pride and Prejudice. New York: Penguin Classics, 2007. Kindle edition.
Austen, Jane. Pride and Prejudice. New York: Penguin Classics, 2008. PDF e-book.
Optionally, you may include details about the print edition of which the digital edition is a reprint.
Austen, Jane. Pride and Prejudice. London: T. Egerton, 1813. Reprint, New York: Penguin Classics, 2008. PDF e-book.
For endnote citations, in place of page numbers, use whatever sort of chapter, section, or location numbers are provided by the e-book.
1. Jane Austen, Pride and Prejudice (New York: Penguin Classics, 2008), Microsoft Reader e-book, chap. 23.
For more details, consult the Chicago Manual of Style section 14.166. The Manual is available at the Reference Desk on the second floor of the Library, and is also available online.