The following chart from the UT Arlington Library Acknowledging Sources tutorial will guide you in your decision:
What is common knowledge? This refers to facts well known by many people and verifiable in five or more sources. Examples:
- Bill Gates is the founder of the Microsoft Corporation.
- There are 60 minutes in an hour.
- Columbus is the capital of Ohio.
If you have any doubts or questions, ask your professor or librarian.
Err on the side of caution: when in doubt, cite!