Schredl, M., Bocklage, A., Engelhardt, J. and Mingebach, T. 2009. Psychological boundaries, dream recall, and nightmare frequency: a new Boundary Personality Questionnaire (BPQ). International Journal of Dream Research. 2, 1 (Apr. 2009), 12–19. DOI:https://doi.org/10.11588/ijodr.2009.1.162.