Ahadi, Suaidi, Nanang Tyasbudi Puspito, Gunawan Ibrahim, Sarmoko Saroso, Kiyohumi Yumoto, and M. Muzli. 2015. “Anomalous ULF Emissions and Their Possible Association With the Strong Earthquakes in Sumatra, Indonesia, During 2007-2012”. Journal of Mathematical and Fundamental Sciences 47 (1):84-103. https://doi.org/10.5614/j.math.fund.sci.2015.47.1.7.