Source:
Stumbrys, Tadas; Erlacher, Daniel; Schredl, Michael (2013). Reliability and stability of lucid dream and nightmare frequency scales. International Journal of dream
Source:
Stumbrys, Tadas; Erlacher, Daniel (2012). Lucid dreaming during NREM sleep: Two case reports. International Journal of dream research, 5(2), pp. 151-155.