Web-based indicated prevention of common mental disorders in university students in four European countries – Study protocol for a randomised controlled trial oleh Peter Musiat, Rachel Potterton, Gemma Gordon, Lucy Spencer, Michael Zeiler, Karin Waldherr, Stefanie Kuso, Martina Nitsch, Tanja Adamcik, Gudrun Wagner, Andreas Karwautz, David Daniel Ebert, Alyson Dodd, Barbara Dooley, Amy Harrison, Emma Whitt, Mark Haselgrove, Helen Sharpe, Jo Smith, Rosie Tressler, Nicholas Troop, Chantal Vinyard, Dennis Görlich, Jenny Beecham, Eva Bonin, Corinna Jacobi, Ulrike Schmidt