While the government seems huge and daunting (a very safe assumption), it's amazing how small the circles are of people doing similar work in the government for different organizations. That makes use of referrals particularly effective. 

In this episode of Myths of Selling to Government sponsored by Government Selling Solutions, host Rick Wimberly tells the story of a young sales protege' who took a risk on a referral, found success and produced a darn fine example on referral selling when trying to win government contracts.