Madsen, Katrine Rich, Damsgaard, Mogens Trab, Rubin, Mark, Jervelund, Signe Smith, Lasgaard, Mathias, Walsh, Sophie, Stevens, Gonneke G. W. J. M., Holstein, Bjørn E.. Springer; 2016. Loneliness and ethnic composition of the school class: a nationally random sample of adolescents.