Comparative effectiveness of three versions of a stepped care model for insomnia differing in the amount of therapist support in internet-delivered treatment: study protocol for a... oleh Pim Cuijpers, Claudia Buntrock, Harald Baumeister, Michael Kühn, Ann-Marie Küchler, Lina Braun, Natalie Bauereiss, Dirk Lehr, Katharina Domschke, David Daniel Ebert, Elena Heber, Charles M Morin, Morten Moshagen, Martina Bader, Kai Spiegelhalder, Abdulwahab Al-Kamaly, Fee Benz, Maike Burkhardt, Patrick Dülsen, Marvin Franke, Lukas Frase, Kathrin Helm, Terry Jentsch, Anna Johann, Andy Maun, Kneginja Richter, Julian Schiel, Laura Simon, Lukas Spille, Hans-Günter Weeß, Dieter Riemann