Kerjasama dalam kegiatan usaha jasa pertambangan menurut Undang-Undang nomor 4 tahun 2009 tentang pertambangan mineral dan batubara = Cooperation in mining services business activity according to Law of the Republic of Indonesia number 4 of 2009 concerning mineral and coal mining / Raja Baringin Grahita Natha - Raja Baringin Grahita Natha, author (Fakultas Hukum Universitas Indonesia, 2013)