Schou-Bredal, Inger, Tine Grimholt, Tore Bonsaksen, Laila Skogstad, Trond Heir, i Øivind Ekeberg. 2021. „Optimists’ and pessimists’ Self-Reported Mental and Global Health During the COVID-19 Pandemic in Norway”. Health Psychology Report 9 (2):160–168. https://czasopisma.bg.ug.edu.pl/index.php/HPR/article/view/5751.