Zou, Q., Zhu, C., Yang, Y., Zuo, X., Long, X., Cao, Q., et al. (2008). An improved approach to detection of amplitude of low-frequency fluctuation (ALFF) for resting-state fMRI: fractional ALFF. Journal of Neuroscience Methods, 172(1), 137-141. doi:10.1016/j.jneumeth.2008.04.012.