Saat, S., N. Mokhtar, T. Zaid, Z. A. Ghani, A. A. M. Isa, A. Darsono, Y. Yusop, F. A.Rahman, S. Husin, M. M. Isa, and M. M. Zin. “The Development of Wireless Power Transfer Technologies for Low Power Applications: An Acoustic Based Approach”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 7, no. 2, Dec. 2015, pp. 129-35,