Yup. Or at least I would. Especially if they are accepted widely as standard or good sources in the industry. It lends more credibility to your arguments, so they're aware you're not just pulling it out of .. the air.
"I realize it's an error, but no one is going to try to do that!" From "Top 10 Stupid Comments from Developers"
Yes, cite the references. Not only does it give credit where it's due, it also lets your management know you aren't the source (and they may very well think you are). This lets them know you may not know all the answers, but you know where to find them, whihc is sometimes better than being a smartypants.
[This message has been edited by sgates (edited 09-06-2001).]
I would write the proposal just as one would write a research paper. It does not seem to be done that way much in the software area and I (being the cynic that I am)get frustrated when I see unsupported statements written as if they are fact (e.g. "It is common. . .").
Also, adding those references will allow people to read further into the topic. It also shows your dedication to the project / idea by displaying the extent of the research you compiled during your assessment.