From Electrical Engineering TA Handbook

Add a citation needed to an article?

The "citation needed" link you just followed is there because another editor felt that the preceding statement was dubious or sufficiently controversial Template:Fact as to demand citation. If you can provide a source to back up the statement, please add it. (Often this is done with the help of citation templates such as {{cite book}}, {{cite news}}, or {{cite web}}.) If not, please exercise extra caution when using the flagged information. If the statement is about a living person, delete the statement.

For information on why statements should be sourced with a citation, see:

• Verifiability, one of Wikipedia's three fundamental policies.
• Reliable sources explains what constitutes reliable sources.

For information on how to provide sources:

• Citing sources

For information about the "citation needed" template itself and how to use it:

• Template:Fact