Studi pembiayaan operasional puskesmas setelah program bok dan pengaruhnya terhadap cakupan pelayanan kesehatan dasar tahun 2010-2012 di Kabupaten Pasaman Barat : studi kasus 4 puskesmas = Study of health centers operational financing after bok program and its effect on primary health care coverage year of 2010-2012 in Pasaman Barat district : case study 4 health centers