Reference:
Tracy E. Herring, Kevin N. Alschuler, Lindsey M. Knowles, Kala M. Phillips, Whitney M. Morean, Aaron P. Turner, Dawn M. Ehde, Differences in correlates of fatigue between relapsing and progressive forms of multiple sclerosis, Multiple Sclerosis and Related Disorders, Volume 54, 2021, 103109,ISSN 2211-0348.
https://doi.org/10.1016/j.msard.2021.103109