Kwon, K. H., Oh, S. H., Lee, J. H. and Kim, T. H. (2010). “An analysis on determining
quality of service criteria dor express bus passengers using the Importance-performance
Analysis (IPA).” Journal of the Koran Society of Civil Engineers, Vol. 30, No. 3D,
pp. 223-229.Kwon, K. H., Oh, S. H., Lee, J. H. and Kim, T. H. (2010). “An analysis
on determining quality of service criteria dor express bus passengers using the Importance-performance
Analysis (IPA).” Journal of the Koran Society of Civil Engineers, Vol. 30, No. 3D,
pp. 223-229.