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van der Werf TS, Mannes GP, Hew JM, Grevink RG, van der Mark TW, Ebels T, Koëter GH.van der Werf TS, et al. Among authors: ebels t.Thorax. 1994 Jul;49(7):723-5. doi: 10.1136/thx.49.7.723.Thorax. 1994.PMID: 8066573Free PMC article.