Pattern recognition of pulmonary disease. Friedman PJ. AJR Am J Roentgenol. 1980 May;134(5):1093-4. doi: 10.2214/ajr.134.5.1093. PMID: 6768260
[A missing link in classification of occupational pulmonary diseases--occupational chronic obstructive lung diseases]. Zinchenko VA, Razumov VV, Gurevich EB. Med Tr Prom Ekol. 2004;(6):33-4. PMID: 15318456
[New and old definitions and COPD terminology]. Salajka F. Vnitr Lek. 2004 Sep;50(9):659-62. PMID: 15580896