Ramayah, T., A. Nasurdin, M. Nasser Noor, and Q. Boon Sin. “The Relationships Between Belief, Attitude, Subjective Norm, and Behavior Towards Infant Food Formula Selection: The Views of the Malaysian Mothers”. Gadjah Mada International Journal of Business, Vol. 6, no. 3, Sept. 2004, pp. 405 -18, https://journal.ugm.ac.id/v3/gamaijb/article/view/14772.