Chicago style has two different systems of source citations.
If you're not sure which style to use in your paper, ask your teacher!
What Do You Cite:
Cite all outside sources whose ideas, theories, or research influenced your research paper. Specifically you site those sources that you:
What Don't You Cite:
Where to Cite:
You need to cite your sources in two places:
What to Include:
For most sources, the information you include in your citation must answer these three questions:
A digital object identifier (DOI) 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.
CMS recommends that when DOIs are available, you include them for both print and electronic sources. The DOI is typically located on the first page of the electronic journal article, near the copyright notice. The DOI can also be found on the database landing page for the article.
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.
Not all publications have DOI numbers assigned to them yet. The resources below show you how to find a DOI number and what to do if there is no DOI:
It's important to make sure you collect all the information you need to cite a source as you gather your information so that you won't need to look it up again, so: