E-HEalth treatment in Long-term Dialysis (E-HELD): study protocol for a multicenter randomized controlled trial evaluating personalized Internet-based cognitive-behavioral therapy... oleh Judith Tommel, Andrea W. M. Evers, Henk W. van Hamersvelt, Sandra van Dijk, Niels H. Chavannes, Lieke Wirken, Luuk B. Hilbrands, Henriët van Middendorp