Maidin, S., A. Mohamed, S. Mohamed, J. H. Wong, and S. Sivarao. “Effect of Multiple Piezoelectric Transducer on Fused Deposition Modeling to Improve Parts Surface Finish”. Journal of Advanced Manufacturing Technology (JAMT), Vol. 12, no. 1(2), 1, pp. 101-16, https://jamt.utem.edu.my/jamt/article/view/4273.