American Academy of Nurse Practitioners www.aanp.org
American Nurses Credentialing Center http://www.nursecredentialing.org/

Nurse Practitioner Association of Maryland www.npamonline.org
Nurse Practitioner Association of the District of Columbia www.NPADC.org
Virginia Council of Nurse Practitioners http://www.vcnp.net/

http://www3.interscience.wiley.com/journal/118489147/home - Link to the American Academy of Nurse Practitioners Online Journal.