Example on how to write an annotated bibliography.
A DOI is a Digital Object Identifier.
It is a unique alphanumeric string assigned by a registration agency (the International DOI Foundation) to identify content and provide a persistent link to its location on the Internet. The publisher assigns a DOI when your article is published and made available electronically.
All DOI numbers begin with a 10 and contain a prefix and a suffix separated by a slash. The prefix is a unique number of four or more digits assigned to organizations; the suffix is assigned by the publisher and was designed to be flexible with publisher identification standards.
American Psychological Association. (2013). What is a digital object identifier, or DOI?. Retrieved from
If you don't see one and want to check, you can go to crossref.org and type in the author's last name and the name of the journal article.
If a DOI is available, you will need to add it to your citation.
Karplus, M. (2010). Dynamical aspects of molecular recognition. Journal of Molecular Recognition, 23(2), 102-104. doi: 10.1002/jmr.1018
If the article does not have a DOI, then you would cite your article with the url of the journal home page.
If you found the article in a database and it is only published in that database, then you can add the database name and accession number
Berman, R. P. (2009). Fused voices: Narrated monologue in jane austen's emma. Nineteenth-Century Literature, 64(1), 1-15. Retrieved from http://ucpressjournals.com/journal.php?j=ncl
Bilger, A.(2009). Women Novelists Before Jane Austen: The Critics and Their Canons (review). Tulsa Studies in Women's Literature 28(1), 201-202. The University of Tulsa. Retrieved October 9, 2013, from Project MUSE database.