Wilson, Julie S and Elborn, J Stuart and Fitzsimons, Donna and McCrum-Gardner, Evie (2011) Do smokers with chronic obstructive pulmonary disease report their smoking status reliably? A comparison of self-report and bio-chemical validation. International Journal of Nursing Studies, 48, (7), pp. 856-862. https://doi.org/10.1016/j.ijnurstu.2011.01.002.