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Ställberg B, Lisspers K, Hasselgren M, Janson C, Johansson G, Svärdsudd K.Ställberg B, et al.Prim Care Respir J. 2009 Dec;18(4):279-86. doi: 10.4104/pcrj.2009.00024.Prim Care Respir J. 2009.PMID: 19455269Free PMC article.
Lisspers K, Ställberg B, Hasselgren M, Johansson G, Svärdsudd K.Lisspers K, et al. Among authors: stallberg b.Prim Care Respir J. 2005 Jun;14(3):147-53. doi: 10.1016/j.pcrj.2005.03.003. Epub 2005 Apr 14.Prim Care Respir J. 2005.PMID: 16701714Free PMC article.
van der Molen T, Østrem A, Stallberg B, Østergaard MS, Singh RB.van der Molen T, et al. Among authors: stallberg b.Prim Care Respir J. 2006 Feb;15(1):35-47. doi: 10.1016/j.pcrj.2005.11.001. Epub 2005 Dec 20.Prim Care Respir J. 2006.PMID: 16701757Free PMC article.