Hoekzema, D., Schooten, G. and van den Berg, E. 2003. Conservation laws, symmetries and elementary particles. Proceedings of the Samahang Pisika ng Pilipinas, 21(1), SPP-2003-WS-PE-03. URL: https://proceedings.spp-online.org/article/view/SPP-2003-WS-PE-03.