АЛТАНХУЯГ, М. Source Apportionment of Air Particulate Matter in Ulaanbaatar City (2017–2019) Using Positive Matrix Factorization. Scientific transaction of the National University of Mongolia. Physics, [S. l.], v. 38, n. 621, p. 55–63, 2025. DOI: 10.22353/physics.v38i621.10084. Disponível em: https://journal.num.edu.mn/physics/article/view/10084. Acesso em: 5 dec. 2025.