@article {198, title = {Circadian Phase Estimation of Healthy Subjects and Sleep-onset Insomnia Patients using Heart Rate Derived Features}, journal = {XIII Congress of the European Biological Rhythms Society Conference Book}, year = {2013}, pages = {155}, author = {Gil, Enrique A and Aubert, Xavier L and M{\o}st, Els IS and Penzel, T. and Beersma, Domien GM} }