TY - JOUR AU - Green, R H; Singh, S J; Williams, J TI - A randomised controlled trial of four weeks versus seven weeks of pulmonary rehabilitation in chronic obstructive pulmonary disease JO - Thorax VL - 56 PY - 2001 DO - 10.1136/thorax.56.2.143 L3 - PubMed-ID: 11209104 SP - 143 EP - 145 N1 - et al. ER -