Arce, E.J.P., Vasquez, J.Z. and Sarmago, R.V. 2010. Influence of lithium and ultrasonic stirring time on the surface morphology of hydroxyapatite prepared via wet chemical precipitation method. Proceedings of the Samahang Pisika ng Pilipinas, 28(1), SPP-2010-PA-58. URL: https://proceedings.spp-online.org/article/view/SPP-2010-PA-58.