1. Operator effort and the measurement of heart-rate variability;Aasman;Human Factors,1987
2. Measuring mental fatigue in normal daily work routines;Aasman,1988
3. Sleepiness as a consequence of shift work;Akerstedt;Sleep,1988
4. Sleepiness at work: Effects of irregular work hours;Akerstedt,1991
5. Temporal factors in human performance and productivity;Alluisi,1982