Wahyuni, Sri, Supriyanto Supriyanto, & Djayus Djayus. " ESTIMASI SEBARAN KUALITAS BATUBARA (ASH CONTENT) MENGGUNAKAN METODE INVERS DISTANCE WEIGHTED (IDW) DAN ORDINARY KRIGING (OK) DI PT. KAYAN PUTRA UTAMA COAL SITE SEPARI, KALIMANTAN TIMUR." GEOSAINS KUTAI BASIN [Online], 2.1 (2019): n. pag. Web. 28 Apr. 2024