Navarro Gil, M. Escolano Marco, C. Montero-Marín, J. Minguez Zafra, J. Shonin, E. García Campayo, J. Efficacy of Neurofeedback on the Increase of Mindfulness-Related Capacities in Healthy Individuals: a Controlled Trial Mindfulness 10.1007/s12671-017-0775-1 2018 2018