Lorensia, A. et al. 2021. Aktivitas Fisik dan Risiko PPOK pada Pengemudi Becak di Surabaya: Physical Activities and COPD Risks in Pedicab Drivers in Surabaya. Jurnal Sains dan Kesehatan. 3, 5 (Oct. 2021), 706–714. DOI:https://doi.org/10.25026/jsk.v3i5.639.