Efficient sources

In your opinion, what is the most efficient source for referrals for a community-based organization?

We really prioritize getting referrals from medical providers in the spirit of coordinated care.  Both the Asthma Home Visit Programs and Breathe Easy at Home program provide a feedback report only to the referrer so the preference is that the referrer be the medical provider.  We do accept referrals from school nurses and on occaision we accept self referrals but still try to get a referral form completed by the medical provider with the clients permission.