A PORTABLE SPECTROPHOTOMETER WITH A VISIBLE LIGHT AS RADIATION SOURCE FOR ACID-BASE CONCENTRATION MEASUREMENTS. PILLAR OF PHYSICS, [S. l.], v. 18, n. 2, p. 96–108, 2025. DOI: 10.24036/w9crvk35. Disponível em: https://pop.ppj.unp.ac.id/index.php/pop/article/view/47. Acesso em: 19 apr. 2026.