Investigating the Efficacy of the Web-Based Common Elements Toolbox (COMET) Single-Session Interventions in Improving UK University Student Well-Being: Randomized Controlled Trial - Jeffrey Lambert; Maria Loades; Noah Marshall; Nina Higson-Sweeney; Stella Chan; Arif Mahmud; Victoria Pile; Ananya Maity; Helena Adam; Beatrice Sung; Melanie Luximon; Keren MacLennan; et al. (Journal of Medical Internet Research)