Kurniawan, P. W. . “PENGARUH POSITIVE REINFORCEMENT TERHADAP HASIL BELAJAR SEJARAH SISWA DI SMA ADIGUNA BANDAR LAMPUNG”. Lentera: Jurnal Ilmiah Kependidikan, vol. 11, no. 1, May 2018, pp. 71-80, https://jurnal.stkippgribl.ac.id/index.php/lentera/article/view/375.