Ingle, L., Rigby, A. S., Nabb, S., Jones, P. K., Clark, A. L., & Cleland, J. G. (2006). Clinical determinants of poor six-minute walk test performance in patients with left ventricular systolic dysfunction and no major structural heart disease. European Journal of Heart Failure, 8(3), 321-325. https://doi.org/10.1016/j.ejheart.2005.08.006