Mithun, S., N. Begum, M. Hossain, S. Ferdousi, and R. Tabassum. “Power Spectral Analysis of Heart Rate Variability in Heavy Workers”. Journal of Armed Forces Medical College, Bangladesh, vol. 7, no. 1, Sept. 2011, pp. 15-19, doi:10.3329/jafmc.v7i1.8620.