Aiming for study comparability in Parkinson's disease: Proposal for a modular set of biomarker assessments to be used in longitudinal studies oleh Stefanie eLerche, Sebastian eHeinzel, Guido Werner Alves, Paolo eBarone, Stefanie eBehnke, Yoav eBen-Shlomo, Henk eBerendse, Bastiaan eBloem, David eBurn, Richard eDodel, Donald eGrosset, Geraldine eHipp, Michele eHu, Meike eKasten, Rejko eKrüger, Inga eLiepelt-Scarfone, Walter eMaetzler, Marcello eMoccia, Brit eMollenhauer, Wolfgang eOertel, Benjamin eRoeben, Uwe eWalter, Karin eWirdefeldt, Daniela eBerg, Daniela eBerg