Basu N, Jones GT, Macfarlane GJ, Druce KL. Identification and validation of clinically relevant clusters of severe fatigue in rheumatoid arthritis. Psychosom Med. 2017 Nov;79(9):1051-8. doi: 10.1097/PSY.0000000000000498
Herring WL, Herrmann JW. The single-day surgery scheduling problem: sequential decision-making and threshold-based heuristics. OR spectrum: quantitative approaches in management. 2012 Apr 1;34(2):429-59.