Spektra, Editor. “BACK MATTER SPEKTRA VOLUME 4 ISSUE 3, DECEMBER 2019”. Spektra: Jurnal Fisika dan Aplikasinya 4, no. 3 (December 31, 2019). Accessed April 16, 2025. http://103.8.12.212:33180/unj/index.php/spektra/article/view/14853.