Personality traits and types predict medical school stress: a six-year longitudinal and nationwide study. - Tyssen, Reidar; Dolatowski, Filip C; Røvik, Jan Ole; Thorkildsen, Ruth F; Ekeberg, ØIvind; Hem, Erlend; Gude, Tore; Grønvold, Nina T; Vaglum, Per (Medical Education, 2007)