P. Wróbel-Knybel, M. Flis, R. Dubiel, and H. Karakuła-Juchnowicz, “What do we know about sleep paralysis?”, Curr Probl Psychiatry, vol. 19, no. 3, pp. 174–184, Nov. 2018, doi: 10.2478/cpp-2018-0014.