The Swiss Primary Hypersomnolence and Narcolepsy Cohort study (SPHYNCS): Study protocol for a prospective, multicentre cohort observational study. - Dietmann A; Wenz E; van der Meer J; Ringli M; Warncke JD; Edwards E; Schmidt MH; Bernasconi CA; Nirkko A; Strub M; Miano S; Manconi M; et al. (Journal of sleep research, 2021)