C. K. Ullrich,V. Dussel,J. M. Hilden,J. W. Sheaffer,C. L. Moore,C. B. Berde and J. Wolfe. Fatigue in children with cancer at the end of life. J Pain Symptom Manage. 2010;40(4):10.1016/j.jpainsymman.2010.02.020.
C. K. Ullrich,V. Dussel,J. M. Hilden,J. W. Sheaffer,C. L. Moore,C. B. Berde and J. Wolfe. Fatigue in children with cancer at the end of life. J Pain Symptom Manage. 2010;40(4):10.1016/j.jpainsymman.2010.02.020.