From Codes > Other Basic Codes > Doctors.  Click the Add button. A window will pop up with a listing of codes that are available for new entries.  Select one of the available codes for the new referral source.  Towards the top there's Referral Type, select the type of referral.  Enter the referral information and click on Save.  

Note: When the Type other than Physician is selected you will only be able to enter a last name.  If you are entering a persons name enter both the first and last name in this field. 

You can add new Referral Type by going to Codes > Status Codes > Referral Type Codes and adding it there.

To print a list of Referral Sources, go to Reports>Doctor>08.28.  Select Non-Doctors (Referral Type >00).  You can also use the option to Print By Referral Type/Name.