G. Kumar, A. Sasidharan, A. Kumar Nair, and B. M. Kutty, “Efficacy of the combination of cognitive training and acoustic stimulation in eliciting lucid dreams during undisturbed sleep - a pilot study using polysomnography, dream reports and questionnaires”, ijodr, vol. 11, no. 2, pp. 197–202, Nov. 2018.