Nur Krisna, D., and Z. Su’ud. “Study Neutronic of Small Pb-Bi Cooled Non-Refuelling Nuclear Power Plant Reactor (SPINNOR) With Hexagonal Geometry Calculation”. Indonesian Journal of Physics, Vol. 23, no. 1, July 2012, pp. 16 -22, doi:10.5614/itb.ijp.2012.23.1.4.