Kholis, I. (2012). KUALIFIKASI WELDING PROCEDURE SPECIFICATION (WPS) DAN JURU LAS (WELDER) BERDASARKAN ASME SECTION IX DI INDUSTRI MIGAS. Swara Patra : Majalah Ilmiah PPSDM Migas, 2(3). Retrieved from https://ejurnal.ppsdmmigas.esdm.go.id/sp/index.php/swarapatra/article/view/81