KOLBA, P. M.; KOTKOWSKI, R. Business Cycles Indicators and Short-term Forecasts of Polish Industry Production Index. Oeconomia Copernicana, [S. l.], v. 4, n. 3, p. 65–79, 2013. DOI: 10.12775/OeC.2013.023. Disponível em: http://economic-research.pl/Journals/index.php/oc/article/view/431. Acesso em: 20 jan. 2022.