Documentation

I like this quote (from http://writing.colostate.edu/guides/researchsources/documentation/credibility.cfm):

"At the core of winning over an audience is the ability to present an argument. Convincing others that your way of thinking is worthy can be very challenging and it will be an uphill battle if you build the foundation of your argument on poorly documented research. At stake is your credibility."

You are trying to build your ethos here... you are perceived as trustworthy if your sources are documented AND if they are considered important or significant voices in your chosen field.

I like this thing about context too (from http://writing.colostate.edu/guides/researchsources/documentation/context.cfm):

"Proper documentation separates the various points-of-view in the source material and helps the reader see the path you followed in developing arguments that support your conclusions."

What I like about this quote is the path analogy. I need to see how you'll get where you're going in order to put faith in your ability to take me on a journey.