K. B. Klingsieck, “Procrastination,”10.1027/1016-9040/a000138__European Psychologist, pp. 24–34, 2013, doi:10.1027/1016-9040/a000138 .

K. B. Klingsieck, “Procrastination: When Good Things Don’t Come to Those Who Wait,”10.1027/1016-9040/a000138__European Psychologist, vol. 18, no. 1, pp. 24–34, 2013, doi:10.1027/1016-9040/a000138 .