“THE HEAVY LOAD OF THE BACKPACK ON THE SHOULDER POSITION AT THE AGE OF 12-15 YEARS AT SMPN 56 SURABAYA”. BIOMA : Jurnal Ilmiah Biologi 13, no. 1 (April 20, 2024): 29–35. Accessed April 30, 2025. https://journal2.upgris.ac.id/index.php/bioma/article/view/375.