Callan, D. E., Tsytsarev, V., Hanakawa, T., Callan, A. M., Katsuhara, M., Fukuyama, H., et al. (2006). Song and speech: Brain regions involved with perception and covert production. NeuroImage, 31(3), 1327-1342. doi:10.1016/j.neuroimage.2006.01.036.