TY - JOUR AU - Si L AU - Greenfield D AU - Kinsman L BT - BMC Health Services Research DO - 10.1186/s12913-018-3316-2 LA - eng PY - 2018 T2 - BMC Health Services Research TI - Hospital length of stay variation and comorbidity of mental illness: A retrospective study of five common chronic medical conditions VL - 18 ER -