Efficacy and cost-effectiveness of Internet-delivered cognitive-behavior therapy for children and adolescents with body dysmorphic disorder: study protocol for a randomized controlled trial - Lorena Fernández de la Cruz; Anita Birovecz; Per Andrén; Karin Melin; Kristina Aspvall; Matti Cervin; Erik Andersson; Maria Silverberg-Mörse; Martina Gumpert; Frida Wickberg; Matteo Bottai; Eva Serlachius; et al. (Trials, 2026)