Onyegiri, Ifeanyichukwu Ebubechukwu, and Sunday Ayoola Oke. 2017. “A grey relational analytical approach to safety performance assessment in an aviation industry of a developing country”. Engineering and Applied Science Research 44 (1):1-15. https://ph01.tci-thaijo.org/index.php/easr/article/view/42857.