It is important to cite your research sources to provide proper credit to those who have influenced your work. As listed on page 15 of the APA manual, "Researchers do not claim the words and ideas of another as their own; they give credit where credit is due (APA Ethics Code Standard 8.11, Plagarism)." To understand plagarism ans self-plagarism, see section 1.10, pages 15-16 of the APA manual.
American Psychological Association. (2010). Publication Manual of the American Psychological Association (6th ed.). Washington, DC: American Psychological Association.
Whether you get your research from a database, blog, or generic website, you need to provide links that will help readers track back to your resources. Most URLs have a short life span so DOIs provide more stable links. If the resource moves to another URL on the internet, its DOI should direct a user to that new location.
See the APA manual, section 6.31 and 6.32, pgs. 187-192 for more information regarding URLs and DOIs for electronic sources.
Sometimes, you can't find a particular piece of information for your reference, e.g. date. What do you do when information is missing? The APA Style Blog has a helpful chart, "How to Write an APA Style Reference When Information Is Missing" (http://blog.apastyle.org/files/missing-pieces---apa-style-reference-table.pdf), with tips.
You need to properly cite your sources whether you use their ideas, words, data, etc. The APA manual, chapter 6, 169-192, explains why and how you can credit your sources properly. Sometimes this even means crediting your source's sources! Crediting your sources consists of two parts: citing references in the text of your document and providing a full list of references.
Here's a quick guide on where to look in the APA manual for help:
The APA manual, chapter 7, pages 193 to 224, shows how to format a wide variety of reseach resources.
Here's the location of some common examples:
Make sure to check the entire chapter for a full list of reference examples.
NOTE: There are some types of resources that aren't covered in the manual or may be more confusing. The American Psychological Association's APA Style Blog (http://blog.apastyle.org/apastyle/) is a great source for additional information on citing and formatting with APA. Here's a few examples: