References

Redelmeier DA, Bayoumi AM, Goldstein RS, Guyatt GH.  Interpreting small differences in functional status: the six minute walk test in chronic lung disease patients.  Am J Respir Crit Care Med. 1997;155:1278-1282.

ZuWallack R, Haggerty MC, Jones P. Clinically meaningful outcomes in patients with chronic obstructive pulmonary disease. Am J Med. 2004;117 Suppl 12A:49S-59S.