Academic Articles (including practice profiles and legislative summaries)
Nonacademic Articles (including white papers, news articles, etc)
How to Moonlight as an "Opted Out" Physician
Federal Regulations (for state regulations please see state by state discussions)
Health Care Sharing Ministries
DPC Practice Mapper
The Official Guide to Starting Your Own Direct Primary Care Practice, by Doug Farrago, MD
Tool kits 
Bagel Checklist (a thorough to-do checklist for new practices)
Ancillary Topics
Supporting Organizations
Vendors (Rx Options, Labs, EMR, etc)