You can use CC-licensed materials as long as you follow the license conditions. One condition of all CC licenses is attribution. Here are some good (and not so good) examples of attribution. Note: If you want to learn how to mark your own material with a CC license visit the Creative Commons site.
Here is a photo. Following it are some examples of how people might attribute it.Examples of attribution
This is a good attribution for material from multiple sources
Title? Specific works are named, eg. "Box-and-whisper Plots"
Author? Different authors noted for the different works.
Source? Original materials are linked for each work
License? The different licenses (Creative Commons Attribution for Collaborative Statistics and Creative Commons Attribution-Noncommercial-ShareAlike for the Khan Academy video) are spelled out and linked for each work
Lastly, it is clear which attribution belongs to which work.
A good rule of thumb is to use the acronym TASL, which stands for Title, Author, Source, License.
Title - What is the name of the material?
If a title was provided for the material, include it. Sometimes a title is not provided; in that case, don't worry about it.
Author - Who owns the material?
Name the author or authors of the material in question. Sometimes, the licensor may want you to give credit to some other entity, like a company or pseudonym. In rare cases, the licensor may not want to be attributed at all. In all of these cases, just do what they request.
Source - Where can I find it?
Since you somehow accessed the material, you know where to find it. Provide the source of the material so others can, too. Since we live in the age of the Internet, this is usually a URL or hyperlink where the material resides.
License - How can I use it?
You are obviously using the material for free thanks to the CC license, so make note of it. Don't just say the material is Creative Commons, because that says nothing about how the material can actually be used. Remember that there are six different CC licenses; which one is the material under? Name and provide a link to it, eg. http://creativecommons.org/licenses/by/4.0/ for CC BY.
→ If the licensor included a license notice with more information, include that as well.
Lastly, is there anything else I should know before I use it?
When you accessed the material originally did it come with any copyright notices; a notice that refers to the disclaimer of warranties; or a notice of previous modifications? (That was a mouthful!) Because that kind of legal mumbo jumbo is actually pretty important to potential users of the material. So best practice is to just retain all of that stuff by copying and pasting such notices into your attribution. Don't make it anymore complicated than it is -- just pass on any info you think is important.
These best practices are based on actual CC license requirements. Noting the title is a requirement of all CC licenses version 3.0 or earlier, optional for 4.0. Noting the author, source, license, and retaining any extra notices is a requirement of all CC licenses. See Devil in the details.
You may satisfy the conditions in (1) and (2) above in any reasonable manner based on the medium, means and context in which the Licensed Material is used. For example, it may be reasonable to satisfy some or all of the conditions by retaining a copyright notice, or by providing a URI or hyperlink associated with the Licensed Material, if the copyright notice or webpage includes some or all of the required information.
There is no one right way; just make sure your attribution is reasonable and suited to the medium you're working with. That being said, you still have to include attribution requirements somehow, even if it's just a link to an About page that has that info. (More on different mediums below.)
Attribution in specific media
As stated above, best practices for attribution apply as reasonable to the medium you're working with. For media such as offline materials, video, audio, and images, consider:
1. Publishing a web page with attribution information. For example, on a webpage featuring your audio recording, provide a credit list of material you used that adheres to best practices above. Doing so allows not only your material, but the materials you attribute, to be found by search engines and other web discovery tools. If possible within the medium, make the Author, Source, and License links the user can follow.
2. Mentioning the credits within the media itself. For example, crediting videos can be a simple list of the materials used with their associated licenses in a screen at the end of a video. For audio, it can be a verbal recitation of credits at the end of the recording.