FEVI SYAIFOELIDA, PUTERI AZMAN, ISZMIR ISMAIL, and M. R. EQWAN, “The Quantification of Two Grading Elements in Satisfaction based on ServQual Approach by Using IPA and Kano Method: Automotive Industry”, Int. j. bus. econ. aff., vol. 1, no. 1, pp. 60-66, Dec. 2016.