Chechko, N., Wehrle, R., Erhardt, A., Holsboer, F., Czisch, M., & Sämann, P. G. (2009). Unstable Prefrontal Response to Emotional Conflict and Activation of Lower Limbic Structures and Brainstem in Remitted Panic Disorder. PLoS ONE, 4(5): doi: 10.1371/journal.pone.0005537.