Adristy, Janet Apta, Rany Adiliawijaya Putriekapuja, and Ika Endrawijaya. “Pengaruh Penerapan Safety Management System Terhadap Kualitas Pelayanan Pemanduan Lalu Lintas Udara Di Perum LPPNPI Kantor Cabang Gorontalo”. Langit Biru: Jurnal Ilmiah Aviasi 13, no. 3 (November 17, 2020): 15 -21. Accessed February 25, 2021. http://journal.ppicurug.ac.id/index.php/jurnal-langit-biru/article/view/367.