title: Retrospective studies.
authors.forename: Nick R
authors.initials: NR
authors.lastname: Anthonisen
mesh_terms: D006801:Humans; D010359:Patient Readmission; D029424:Pulmonary Disease, Chronic Obstructive; D012189:Retrospective Studies
references.citation: Can Respir J. 2009 Jul-Aug;16(4):e43-9
references.pmid: 19707601