What don't you have to cite?
- Common knowledge:
Well-known information that your readers are already familiar with. For example, in a math paper you wouldn't need to cite a source for the Pythagorean Theorem (the equation relating the lengths of the sides in a right triangle).
Other examples include chemical symbols (e.g. CO2 for carbon) or scientific names of plants and animals.
- Widely known facts:
The first manned moon landing occurred in 1969
George Washington was the first president of the United States.
- Widely known ideas:
Heisenberg is generally regarded as the father of quantum mechanics.
- Your own ideas!