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4. Trends and characteristics of United States out-of-hospital births 2004-2014: new information on risk status and access to care;MacDorman;Birth,2016
5. Commission for the Accreditation of Birth Centers Indicators of compliance with standards for birth centers. Reference Edition 1.0. St. Paul, MI. https://www.birthcenteraccreditation.org/wp-content/uploads/2014/02/CABC_IndicatorsRefEd_1-0-2015-0901.pdf