"Fatigue." . . "Efficiency." . . "Armed Forces-NRC Committee on Bio-astronautics. Panel on Psychology." . . "Physical Exertion." . . . . . . "Human performance as a function of the work-rest cycle; a review of selected studies" . "Human performance as a function of the work-rest cycle a review of selected studies"@en . . . . . . . . . . . . . . . .