“DETERMINATION OF MINING ZONING ANDESITE, SIRTU AND TRAS MATERIALS IN PURBALINGGA DISTRICT CENTRAL JAVA”. Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics, vol. 3, no. 2, Dec. 2020, pp. 68-77, https://doi.org/10.15408/fiziya.v3i2.17934.