Yatini, Erna Apriliani, and Soetrisno. 2005. “enentuan oefisien aya ngkat esawat erbang ayang erhadap erakan ngin ertikal”. imits: ournal of athematics and ts pplications 2 (1):9. https://journal.its.ac.id/index.php/limits/article/view/5302.