Medicare Physician Guide: A Resource for Residents, Practicing Physicians, and Other Health Care Professionals

http://www.cms.hhs.gov/MLNProducts/downloads/physicianguide.pdf

Official ICD-9-CM Guidelines

http://www.cdc.gov/nchs/icd.htm

Medicare Learning Network- Many free educational materials from CMS

http://www.cms.hhs.gov/MLNGenInfo/

American Academy of Professional Coders

http://www.aapc.com/

Documentation Guidelines for Evaluation and Management Services

http://www.cms.hhs.gov/MLNEdwebGuide/25_EMDOC.asp