http://www.cms.gov/Medicare/Provider-Enrollment-and-Certification/GuidanceforLawsAndRegulations/Downloads/ESRDCoreSurveyFieldManual.pdf
http://www.nraa.org/files/2012%20Conference%20Handouts/CMS_New_Core_Survey_and_other_CMS_News__Judith_Kari_CMS.pdf