Choiruddin, Irfan. 2012. “STRATEGI PENCAPAIAN ANGKA KREDIT WIDYAISWARA”. Swara Patra : Majalah Ilmiah PPSDM Migas 2 (3). http://ejurnal.ppsdmmigas.esdm.go.id/sp/index.php/swarapatra/article/view/75.