Vendmard, Yohanes, Agung Sutrisno, and Johan S C Neyland. 2016. “ANALISIS KELUHAN PELANGGAN TERHADAP DISTRIBUSI MINYAK PELUMAS DI MANADO”. Jurnal Poros Teknik Mesin UNSRAT 5 (1). https://ejournal.unsrat.ac.id/v3/index.php/poros/article/view/11648.