Oei, Costantinus, 		Gultom, Maran, 		Ranteallo, Obet Takke, 		Wakarmamu, Thobby, 		Liga, Marthen, 		Hartiningsih, Endang, 		Numberi, Johni, AND 		Silo, Akbar.
" PERFORMANCE ANALYSIS OF THE ELECTRIC TROLLEY OF OXYGEN CYLINDERS BASED ON THE ROAD SLOPE" <em>ROTOR</em> [Online], Volume 16 Number 1 (27 June 2023)